Sean's SSD Buyers Guide & Information Thread

What is this?
This is for those of you trying to choose b/w which SSD to purchase and for those of you who want to learn a little about SSDs in general as well. If you have any additions or questions, by all means feel free to post a question in the thread on anything SSD related and I will be sure to try and answer it for you.

Fell free to chat about with the other members about SSDs and other flash storage here as well.


Index:
(Click on a specific section to jump to it)

• Intro to SSDs
• SSD Components
• Maintenance
• SSD Pros and Cons
• The Do's and the Don'ts
• Sean's recommended SSDs
• Installation
• Benchmarks by OCN members
• Links and extra information

Special thanks to: Warning: Spoiler! (Click to show)

What is a SSD?
Solid state is term that refers to electronic circuitry that is built entirely out of semiconductors. The term was originally used to define those electronics such as a transistor radio that used semiconductors rather than vacuum tubes in its construction. Most all electronics that we have today are built around semiconductors and chips. In terms of a SSD, it refers to the fact that the primary storage medium is through semiconductors rather than a magnetic media such as a hard drive.

A solid-state drive, sometimes called a solid-state disk or electronic disk, is a data storage device that uses solid-state memory to store persistent data with the intention of providing access in the same manner of a traditional block i/o hard disk drive. Now, you might say that this type of storage already exists in the form of flash memory drives that plug into the USB port. This is partially true as solid state drives and USB flash drives both use the same type of non-volatile memory chips that retain their information even when they have no power. The difference is in the form factor and capacity of the drives. While a flash drive is designed to be external to the computer system, an SSD is designed to reside inside the computer in place of a more traditional hard drive.

SSDs are distinguished from traditional magnetic disks such as hard disk drives (HDDs) or floppy disk, which are electromechanical devices containing spinning disks and movable read/write heads, in contrast, SSDs use microchips that retain data in non-volatile memory chips and contain no moving parts. Compared to electromechanical HDDs, SSDs are typically less susceptible to physical shock, are silent, have lower access time and latency, but are more expensive per gigabyte (GB). SSDs use the same interface as hard disk drives, thus easily replacing them in most applications.

So how exactly do they do this? Well, an SSD on the outside looks almost no different than a traditional hard drive. This design is to allow the SSD drive to put in a notebook or desktop computer in place of a hard drive. To do this, it needs to have the standard dimension as a 1.8, 2.5 or 3.5-inch hard drive. It also uses the common SATA interface so that it can easily be placed into any PC as a hard drive would.

So, to the consumer, a SSD is just another storage device for their computer which runs at far faster speeds than a traditional HDD.

To start you off you may want to look at some of these links:
(link)
(link)
(link)
(link)

What parts are SSDs comprised of?
Well, SSDs are comprised of a few different main components, now what are they?

• 
  
• SSD Controllers:
  Every SSD includes a controller, just as does a HDD, that incorporates the electronics that bridge the NAND memory components to the host computer. The controller is an embedded processor that executes firmware-level code and is one of the most important factors of SSD performance. There are numerous circuits and programming required for the operation of the device. Some of the functions performed by the controller include encryption and compressing data before it is written to the drive as well as:
  
  
  Read And Write Disturbs - The act of reading from or writing to a cell can cause adjacent cells to change state. This is known as bit-flop and has to be monitored for each read and write.
  
  Error Correcting Code (ECC) - Used to insure that data read, written or stored has not been unintentionally altered.
  
  Invalid Block Management - Blocks that contain cells that are not capable of properly storing data must be mapped out of the user accessible memory range before data is stored. The blocks also need to be tracked for the life of the drive.
  
  Power data protection - Needed to guard against the involuntary program/erase of cells during power transitions.
  
  Garbage Collection - Optimize free space to reduce erase before program operations.
  
  Wear Leveling - Blocks are monitored for the number of write cycles that have been performed. The blocks are reused in an ascending order starting with the blocks that have gone though the fewest write cycles.
  
  
  Some common SSD controller developers include:

  • Samsung
  • Marvell
  • SandForce (Now owned by LSI) - SandForce controllers are the only devices with a compression algorithm in real time. Basic, it minimizes the impact of specific submissions on the Flash.
  • Toshiba
  • Indilinx (owned by OCZ.)
  • Intel
  • JMicron
  
  
• Memory:
  Most SSDs use NAND flash memory because of the lower cost compared to DRAM. Flash memory SSDs are slower than DRAM SSDs which are mostly used in enterprise applications and not available to the consumer market.
  
  
  NAND Flash Memory - NAND flash memory is a type of non-volatile storage technology that does not require power to retain data. This is the equivalent of a HDD's platters. There are two types of flash memory, NAND and NOR. The names refer to the type of logic gate used in each memory cell. (Logic gates are a fundamental building block of digital circuits). NOR flash was first introduced by Intel in 1988. NAND flash was introduced by Toshiba in 1989. The two chips work differently. NAND has significantly higher storage capacity than NOR. NAND flash has found a market in devices to which large files are frequently uploaded and replaced. MP3 players, digital cameras and USB drives use NAND flash. NOR flash is faster, but it's also more expensive. NOR is most often used in mobile phones. An important goal of NAND flash development has been to reduce the cost per bit and increase maximum chip capacity so that flash memory can compete with magnetic storage devices like hard disks. New developments in NAND flash memory technology are making the chips smaller, increasing the maximum read-write cycles and lowering voltage demands.
  
  

  0's and 1s:
  To learn about how NAND works at a technical level read this: (link)
  
  Tunneling is used to alter the placement of electrons in the floating gate. An electrical charge is applied to the floating gate. The charge enters the floating gate and drains to a ground. This charge causes the floating-gate transistor to act like an electron gun. The excited electrons are pushed through and trapped on other side of the thin oxide layer, giving it a negative charge. These negatively charged electrons act as a barrier between the control gate and the floating gate. A special device called a cell sensor monitors the level of the charge passing through the floating gate.
  
  NAND flash memory uses floating gate MOSFET transistors. Their default state is when the charge is over the 50%. If the flow through the gate is above the 50% threshold, it has a value of 1. When the charge passing through drops below the 50% threshold, the value changes to 0.
  
  0's are data, 1's is erase....the fundamental laws of MLC NAND dictate this. You only write the 0's when you write data to NAND.
  
  So in an erased state the NAND has to report a 1.
  
  Lower priced drives usually use multi-level cell NAND. MLC NAND is what is in almost all consumer SSDs. Higher priced SSDs usually use single-level cell NAND; these drives are usually used for enterprise applications due to better durability. SLC NAND cost about 3 times as much as a MLC NAND.
  
  
  Single-level Cell (SLC) NAND - SLC NAND can store only one data bit per NAND flash cell. This leads to faster transfer speeds, higher cell endurance, and lower power consumption. The downside to SLC chips used in SSDs is the manufacturing cost per megabyte and total capacity which is less per NAND cell than MLC. SLCs are intended for the high-end consumer and server market and they have approximately 10 times more endurance compared to MLC.
  
  Multi-level Cell (MLC) NAND - MLC NAND stores two bits per NAND flash cell. Storing more bits per cell achieves a higher capacity and lower manufacturing cost per megabyte. MLC SSDs are designed for the mainstream consumer market and are much faster compared to standard hard disk drives. MLC SSDs are improving with faster and more efficient technologies and are being adopted into the high-end consumer and server markets.
  
  Endurance Multi-level Cell (eMLC) NAND - eMLC NAND is basically more expansive MLC flash with better endurance.
  
  More info here: (link)
  
  Triple Level Cell (TLC) NAND - TLC NAND stores three bits per cell. However P/E cycles for TLC NAND is significantly lower than that of MLC NAND.
  
  More info here: (link)
  
  Now out of the types of NAND (SLC, eMLC, and MLC) you can get NAND that operate at different speeds. The communication bus between the flash and the controller is also important, it can be either asynchronous, synchronous, or Toshiba, SanDisk, and Samsung's NAND, similar to the synchronous, Toggle-Mode DDR. This is important when determining the SSD you want. Toggle-Mode DDR and Synchronous NAND are preferred over much slower Asynchronous NAND. Toggle-Mode DDR and Synchronous NAND fare far better than Asynchronous NAND with compressed data.
  
  
  Toggle-Mode Double Data Rate (DDR) - Toggle-Mode NAND is a DDR NAND solution designed to consume less power than synchronous DDR NAND flash by eliminating the clock signal typically used in synchronous DDR memories. Toshiba DDR Toggle-Mode 1.0 NAND has a fast interface, rated at 133 megatransfers/second (MT/s). With an asynchronous interface similar to that used in conventional NAND, the Toggle-Mode DDR Flash NAND requires no clock signal, which means that it uses less power and has a simpler system design when compared to competing synchronous NAND alternatives. The DDR interface in Toggle-Mode NAND uses a Bidirectional DQS to generate input/output signals (I/Os) using the rising and falling edge of the write erase signal.
  
  The bi-directional data signal also ensures scalability to future higher frequency operations. Toshiba is working with JEDEC on a new standard for the most advanced high-performance NAND flash memory, a DDR NAND flash with a 400Mbps interface. This next generation Toggle-Mode DDR NAND 2.0 is targeted to provide a three-fold increase in interface speed over Toggle DDR 1.0, and a ten-fold increase over the 40Mbps single data rate NAND that is widely used today.
  
  Synchronous - Faster, more expensive *Currently under revision*
  Asynchronous - Slower, less expensive *Currently under revision*
  
  More info on Asynchronous NAND and Synchronous NAND here: (link)
  
  
  The performance of the SSD can scale with the number of parallel NAND flash chips used in the device. A single NAND chip is relatively slow compared to when when multiple NAND chips that operate in parallel. The bandwidth scales and the high latencies can be usually be hidden. Micron and Intel initially made faster SSDs by implementing data striping (similar to RAID 0) and interleaving in their architecture. This enabled the creation of SSDs with 250 MB/s effective read/write speeds with the SATA 3 Gb/s interface in 2009. Two years later and continuing to leverage this parallel flash connectivity, SandForce released consumer-grade SATA 6 Gb/s SSD controllers which support 500 MB/s read/write speeds.
  
  
  NAND manufactures include:

  • Micron Technology, Inc.
  • Intel Corporation
  • Hynix Semiconductor
  • Phison Electronics Corp.
  • SanDisk Corporation
  • Toshiba
  • Samsung
  • Sony Corporation
  • Spansion

  
  Some NAND groups include:

  • ONFi (Open NAND Flash Interface) Working Group
  • IMFT (Intel Micron Flash Technologies)
  • Flash Forward (Sandisk and Toshiba)
  
  
• Cache or Buffer:
  A flash-based SSD typically uses a small amount of DRAM as a cache, similar to the cache in hard disk drives. A directory of block placement and wear leveling data is also kept in the cache while the drive is operating. Data is not permanently stored in the cache. SandForce does not use an external DRAM cache on their designs, but still achieve very high performance. Eliminating the external DRAM enables a smaller footprint for the other flash memory components in order to build even smaller SSDs.
  
  
• Battery or super capacitor:
  Another component in higher performing SSDs is a capacitor or some form of battery. These are necessary to maintain data integrity such that the data in the cache can be flushed to the drive when power is dropped; some may even hold power long enough to maintain data in the cache until power is resumed. In the case of MLC flash memory, a problem called lower page corruption can occur when MLC flash memory loses power while programming an upper page. The result is data written previously and presumed safe can be corrupted if the memory is not supported by a super capacitor in the event of a sudden power loss. This problem does not exist with SLC flash memory.
  
  
• Host Interface
  The host interface is not specifically a component of the SSD, but it is a key part of the drive. The interface is usually incorporated into the controller. The interface is generally one of the interfaces found in HDDs.
  
  
  Types include:

  • Serial ATA
  • M.2 (NGFF)
  • Serial Attached SCSI (SAS)
  • Fibre Channel
  • PCI Express

How is a SSD maintained?
Basically they maintain themselves, there are many things that SSD manufactures do to make sure the drive lasts like over provisioning, having garbage collection, and wear leveling built into the drive. Here I am going to talk about the main points of what an SSD does to maintain itself.

In a nutshell, all SSDs have garbage collection. TRIM simply optimizes it. It is not needed, but preferred to have enabled as it reduces write amplification and speeds up garbage collection.

• 
  
• Garbage Collection:
  Data is written to the Flash memory in units called pages (made up of multiple cells). However, the memory can only be erased in larger units called blocks (made up of multiple pages). If the data in some of the pages of the block are no longer needed (also called stale pages), only the pages with good data in that block are read and re-written into another previously erased empty block. Then the free pages left by not moving the stale data are available for new data. This is a process called garbage collection (GC). All SSDs include some level of garbage collection, but they may differ in when and how fast they perform the process. Garbage collection is a big part of write amplification on the SSD. Reads do not require an erase of the Flash memory, so they are not generally associated with write amplification. In the limited chance of a read disturb error, the data in that block is read and rewritten, but this would not have any material impact on the write amplification of the drive. The process of garbage collection involves reading and rewriting data to the Flash memory. This means that a new write from the host will first require a read of the whole block, a write of the parts of the block which still include valid data, and then a write of the new data. This can significantly reduce the performance of the system. Some SSD controllers implement background garbage collection (BGC), sometimes called idle garbage collection or idle-time garbage collection (ITGC), where the controller uses idle time to consolidate blocks of Flash memory before the host needs to write new data. This enables the performance of the device to remain high. If the controller were to background garbage collect all of the spare blocks before it was absolutely necessary, new data written from the host could be written without having to move any data in advance, letting the performance operate at its peak speed. The trade-off is that some of those blocks of data are actually not needed by the host and will eventually be deleted, but the OS did not tell the controller this information. The result is that the soon-to-be-deleted data is rewritten to another location in the Flash memory increasing the write amplification. In some of the SSDs from OCZ the background garbage collection only clears up a small number of blocks then stops, thereby limiting the amount of excessive writes. Another solution is to have an efficient garbage collection system which can perform the necessary moves in parallel with the host writes. This solution is more effective in high write environments where the SSD is rarely idle. The SandForce SSD controllers and the systems from Violin Memory have this capability. Also, GC can get into a "stuck" phase where it takes a long time (or never) is able to clean the drive. This has happened to drives in the last year.
  
  
• TRIM:
  In computing, a TRIM command allows an operating system to inform a solid-state drive (SSD) which blocks of data are no longer considered in use and can be wiped internally. While TRIM is frequently spelled in capital letters, it is not an acronym; it is merely a command name. TRIM was introduced soon after SSDs started to become an affordable alternative to traditional hard disks. Because low-level operation of SSDs differs significantly from traditional hard disks the typical way in which operating systems handle operations like deletes and formats (not explicitly communicating the involved blocks/pages to the underlying storage medium) resulted in unanticipated progressive performance degradation of write operations on SSDs.
  
  TRIM enables the SSD to handle garbage collection overhead that would otherwise significantly slow down future write operations to the involved blocks in advance. More recent SSDs will often contain internal idle/background garbage collection mechanisms that work independently of TRIM; although this successfully maintains their performance even under operating systems that do not (yet) support TRIM, it has the associated drawbacks of increased write amplification and wear of the flash cells without TRIM.
  
  TRIM can be initiated in Windows by actions such as emptying the Recycle Bin, but the SSD must also execute the command.
  
  Windows will report that TRIM is enabled even if the SSD doesn't support it. If it sees a HDD with a rotational speed of 0 (ie. an SSD), TRIM gets enabled.
  
  OSes that support TRIM include:
  • Win 7
  • Linux distros since 2010
  • Mac OSX lion
  
  
• TRIM and GC, how they work together:
  All newer SSDs run GC, they are designed to, it's built into their firmware's code. That's why certain GC routines works better than others. The SSD manufacturer "decides" how the GC cycle is implemented by the SSD in the firmware coding. The manufacturer decides this based on what they want to accomplish as average performance for their drives. The things that are predominantly taken into account in developing how the actual GC routine will run are TRIM, background garbage collection and write amplification. TRIM by itself does nothing for the SSD's data. A TRIM command from the OS only tells the SSD, that data on the SSD is no longer required by the OS, nothing more. This may help in understanding what TRIM is, and what it is not. As you are already aware, when you delete a file on your computer, the OS doesn’t actually delete it. The OS, in its file allocation table, only marks the area as free, to be re-used when needed again. This means the data associated with this area of the SSD (or HDD) is no longer considered valid by the OS. The problem is that the drive doesn’t know that the OS did this. Remember, with an SSD, (unlike a magnetic HDD) it is the drive's controller that actually manages the data on the drive, not the OS. With a magnetic HDD, it's not important that the HDD knows what the OS did, because it is the OS that manages the HDD's data allocation units. The OS has the ability to tell the HDD to write over the data whenever/wherever it wants. Step in SSD... The OS no longer has control as to where data is written. All it can do is send data to be written, to the SSD. The SSD then becomes responsible for the data's location on the drive. Even though you have deleted a file, and the OS considers the file deleted, has freed the location in it's data map...etc, the SSD still considers the data valid. When the SSD initiates its Garbage Collection cycle (as mentioned before, as it nears idle), the SSD begins to consolidate blocks of data to free up space. With or without TRIM, The SSD must copy all of the data it considers valid to a new block, before it can erase the current block it is working on. The TRIM command that had been previously sent to the SSD from the OS, helps the SSD to "get on the same page" with the OS. Without the TRIM command being sent to the SSD, it typically would not know a page is considered invalid by the OS, unless the LBA associated with it had been previously rewritten by the SSD. Trim is simply the function of the operating system telling the drive that a page is no longer valid. It does not delete files, or clear pages. But TRIM does help SSDs in a few ways. Usually the GC routine won't have to compare it's entire file data table to that in the OS's. This helps to reduce write amplification (the number of times an SSDs cells are written to), because during GC, the SSD will not/does not need to copy invalid (deleted) pages. There will also be fewer pages for the SSD to copy, which speeds up the process of freeing up partially valid blocks. Again, this is a function of the SSD's GC routine, not TRIM. Garbage collection will also work without TRIM. How effectively is based on the SSDs Firmware. Without TRIM, the GC cycle usually takes a little longer, is slightly less effective, but for other than benchmarks, will usually produce nearly the same results (un-noticable to the end user). This was not always the case with older SSDs.
  
  
• Over-provisioning:
  Over-provisioning (sometimes spelled as OP, over provisioning, or overprovisioning) is the difference between the physical capacity of the flash memory and the logical capacity presented through the operating system (OS) as available for the user. During the garbage collection, wear-leveling, and bad block mapping operations on the SSD, the additional space from over-provisioning helps lower the write amplification when the controller writes to the flash memory.
  
  When an SSD is almost full, this could cause problems. Even for writing a small amount of data you need an completely empty block. For this reason SSDs have over-provisioning, which means more storage capacity present than is available. That this is possible without making consumers feel cheating is thanks to manufacturers of traditional hard disks.
  
  1. The first level of over-provisioning comes from the computation of the capacity and the use of units for gigabyte (GB) where in fact it should be written as gibibyte (GiB). Both HDD and SSD vendors use the term GB to represent a decimal GB or 1,000,000,000 (10^9)bytes. Flash memory (like most other electronic storage) is assembled in powers of two, so calculating the physical capacity of an SSD would be based on 1,073,741,824 (2^30) per binary GB (GiB). The difference between these two values is 7.37% ((2^30-10^9)/10^9). Therefore a 128 GB SSD with 0% over-provisioning would provide 128,000,000,000 bytes to the user. This initial 7.37% is typically not counted in the total over-provisioning number. A 500 GB hard disk only has 466 GB available, also referred to as GiBs. A 256 GB SSD has 256 actual gigabytes (GiBs), but keeps 7.3 percent from being available to the OS. The rest is reserved for over-provisioning to make the controller more efficient.
  
  2. The second level of over-provisioning comes from the manufacturer. This level of over-provisioning is typically 0%, 7%, or 28% based on the difference between the decimal GB of the physical capacity and the decimal GB of the available space to the user. As an example, a manufacturer might publish a specification for their SSD at 100 GB, 120 GB or 128 GB based on 128 GB of possible capacity. This difference is 28%, 7% and 0% respectively and is the basis for the manufacturer claiming they have 28% of over-provisioning on their drive. This does not count the additional 7.37% of capacity available from the difference between the decimal and binary GB. SSDs with a SandForce controller have 256 GB worth of memory chip capacity, but are sold as 240 GB SSDs and make 223 GB available to the OS. That's 12 percent of over-provisioning.
  
  3. The third level of over-provisioning comes from end users to gain endurance and performance at the expense of capacity. Some SSDs provide a utility that permit the end user to select additional over-provisioning. Furthermore, if any SSD is set up with an OS partition smaller than 100% of the available space, that unpartitioned space will be automatically used by the SSD as over-provisioning as well. Over-provisioning does take away from user capacity, but it gives back reduced write amplification, increased endurance, and increased performance. It is basically the same a "short stroking" a mechanical HDD. For example. You have a 128GB drive. You decide that you are going to format your primary partition to 120GB and leave the remainder of the drive "unallocated". This will leave an additional 8GB of, "ready to be written to", space that the drive will use for over provisioning. There is also an ATA command that can be used to set this space, but it is just easier to not use all of the space of the drive while partitioning.
  
  Even so user over provisioning via partition size is counterproductive. Users should not need to do this, all they are doing is wasting usable space on the drive. Normal consumers do not need to protect from wear and tear. They are not doing a ton of write amplification. Modern controllers, like SandForce, lower write amp in write in half. It is meant to give a larger backup of NAND in case of cell failure for server SSDs doing, for example, over 10,000 writes in a day.
  
  The only reason to do it on a consumer level I can think of is to make sure you do not fill up the whole drive with data so you can have some spare if you do fill it up. Even then there is still that ~7% from the first level talked about earlier.
  
  
• Wear Leveling:
  Wear leveling is the process of the ssd understanding how many times each cell of memory has been written to and then ensuring that all are all written to evenly. After all, the life span of the ssd is dependent on the total number of writes that are written to and this has been coined as ‘write endurance’. Unlike the hard drive which stores information in a static location, the SSD will move information around on a continuous basis without your knowledge to ensure that all cells wear evenly, thus affording a longer lifespan for the ssd. By also doing this, the drive can ensure that only the valid information is used, leaving blocks to be cleaned up by TRIM or ITGC, again without the knowledge of the user. Just as an example of how durable these drives are click the following link. (SSD Endurance after 900000GB)
  
  Garbage collection in the SSD does not care about partitions being set away for over provisioning and what not, it is only concerned about the free space and will use it if it is there for wear leveling.

What are the Pros?
Now that you know all the ins and outs of a SSD, why should you get one?

• Speed:
  No more HDD bottle neck! Getting a SSD is the best upgrade you can do for your computer. You will feel the difference. Not even a new processor will feel as fast as the HDD to SSD upgrade. OS boot time will be ~ 10-20 seconds depending on drive and configuration. SSDs are on average over 40 times faster than HDDs in random 4K reads and writes. This means that day to day use will be a much better experience for the user. Programs open near instantly, errors get worked out quicker, and everything just works smoother. Also, with this fast random read and write performance you can rum multiple VMs at once and never get a hick-up. On top of that SSDs usually are 2-5 times faster in sequential reads as well. This means games and other sequential data such as movies, photos, music and other large files will load far faster than on a standard 7200rpm HDD. Now, sequential speeds are not really what make SSDs so fast and desirable for the OS. It is their 4K read speeds and access times. 500+ sequential reads on SATA 3 is a nice upgrade from the 100MB/s on HDDs, but the 4K reads are usually 20-40 times faster than that of a hard drive! (~20MB/s vs .5MB/s!) The faster the 4K read speeds the faster your system will be. And another good thing about NAND flash storage is the extremely quick access times! For example a normal HDD will have ~15ms access times while a SSD will have .1ms! This mainly why they are so fast.
  
  In terms of gaming SSDs help a lot with texture loading and level loading. With large levels load times can be dropped by over 50%. Also, due to the fast access times many textures will load near instantly and give you more consistent FPS overall. In turn that will give you an overall better gaming experience.
  
  
• Reliability:
  Reliability is also a key factor for portable drives. Hard drive platters are very fragile and sensitive materials. Even small jarring movements from an impact can cause the drive to be completely unreadable. Since the SSD stores all its data in memory chips, there are no moving parts to be damaged in any sort of impact.
  
  
• End Life Data Integrity
  When a hard drive reaches end life and crashes, the information is gone. When a SSD reaches end life, it does not crash. It simply prevents further writing to the SSD and all information contained is fully accessible. In fact, there have yet to be any predictions as to how long this information will last other than the life of the NAND flash memory for which the data is stored.
  
  
• Power Usage:
  The power usage is a key role for the use of solid state drives in portable computers. Because there is no power draw for the motors, the drive uses far less energy than the regular hard drive. Now, the industry has taken steps to address this with drive spin downs and the development of hybrid hard drives, but both of these still use more power. The solid state drive will consistently draw less power then the traditional and hybrid hard drive.
  
  One thing to not with the power usage is that NAND flash memory can hold a charge for about 10 years or slightly less when not plugged into a power source. So I would say you are fine to leave data on a SSD for storage for 7-8 years time before replugging it into a system to maintain data integrity.
  
• Heat:
  With less power they also make less heat. So your system will stay cooler, whether it is a laptop or a desktop.
  
  
• Size and Weight:
  They are usually in 2.5" form factor, 7-9.5mm thick, and are very light weight compared to HDDs. They are an ideal upgrade for a laptop especially.
  
  
• Sound:
  They are dead silent since they have no moving parts. Perfect for those of you who want a silent PC.
  
  
• Lifespan:
  The longevity of SSDs, or lack of, as the case may be, is blown way out of proportion. Most will probably be surprised to hear NAND memory actually has a higher MTBF (Mean Time Before Failure) than DRAM. How often does your DRAM fail once you've passed the 3 month mark with it? Most SSDs have a MTBF of about 1 million hours plus (it's actually 1 million writes). Has anyone actually done the math on that? It works out to be over 20 yrs of continuous use; 24/7. This assumes adequate "free" space. A "full" drive (using more than 85% of its usable space) has very few (in the number of storage locations), blocks/pages/cells to work with in its normal day to day operations. This forces the SSD to use and reuse the same cells over and over again. The algorithm used for wear leveling goes to hell when the drive doesn't have enough free space for moving data. The cells that comprise the free space end up being used over and over, and will fail much sooner than those on the rest of the drive.
  
  A lot (some say most) of the longevity of a drive actually has to do with the amount of "over provisioning" on the drive. Over provisioning is like spare parts for the drive (actually spare NAND). Artificial numbers, but say you buy a 128GB SSD. That SSD may actually contain up to 10% (12GB) of additional NAND that is not calculated into the drive size stated by the manufacturer.
  
  NAND memory can/and does go bad, it's a fact of NAND life. The cells of NAND are little electronic traps, that trap electrons with "gate" technology (although not exactly the same), just like the gates of a transistor that runs your CPU. These "gates" over time can leak, be susceptible to leakage from adjacent cells, or just plain fail, among other things that render their use as problematic.
  
  When an SSD's controller (firmware) determines that a cell is no longer performing like it should, it will replace the data location with one of the over provisioned blocks/pages, and no longer use the "defective" location. Depending on the firmware's coding, this is usually done on a "page" level (4 Kilobytes of space). It is basically the same as when a magnetic HDD marks a sector of its spinning platter as "bad"; although the HDD doesn't have the "spare parts" to replace the bad sector.
  
  Just as an example of how long these drives will last click the following link. (SSD Endurance after 900000GB)
  
  Simply put, you can usually get 5-20 years depending on the NAND and usage of the drive. 200+TB of write life. Currently a 256GB Samsung 830 has had over 2 PB of data written to it and is still going strong! That is crazy for a MLC consumer drive! Normally a good quality drive will last 500TB-1PB, let alone 2PB!

What are the cons?
As with everything in life there are some cons to SSDs, but what are they?

• Less capacity for the price.
• May need a 2.5" to 3.5" adapter.
• Constant firmware updates, but I find that is a good thing.
• Also, performance loss if used in IDE mode or if your alignment is off, but that is with all HDDs and SSDs.
• If you get a SandForce drive you could encounter a few things such as random BSODs, freezing, stuttering and the drive disappearing in the BIOS/UEFI of your mobo, but that should all be fixed with the newest firmware that is out for them.
• SSD write performance may degrade when the drive is close to being filled or if you are constantly writing and erasing data to the drive without ample time for GC to take effect. The thing is that SSDs need some "clean" pages when writing data. Otherwise, they have to do a read-modify-write of a "dirty" block instead of just a write to a "clean" page. This process is basically garbage collection at run time and impacts your real time usage rather than preemptive garbage collection. So if you have little free space left and then pound the SSD with a bunch of random writes and do not allow the SSD to clean itself, the can be a noticeable performance degradation.

Do's

• Treat it as you would any other drive.
• Use one as a OS drive over a HDD
• Install all your apps/programs to the SSD
• Make sure defrag is disabled for our SSD

Don'ts

• Don't bother to move your page file off the SSD
• Don't worry about the amount of writes to your SSD
• Don't full format your SSD
• Do not defrag a SSD
• When you Secure Erase with Parted Magic do not bother use the "enhanced/advanced method"
• Do not use DBAN or similar programs to erase your SSD's data. It doesn't work properly. Use Secure Erase instead.

Why you shouldn't defrag a SSD:
Basically a SSD never needs defragmenting because it doesn't matter where the data is on the drive, they have ~.1 access time to anywhere on the the SSD's NAND cells and is always the same. All defragging does to an ssd is reduce its life by moving the data around on the drive.

There is a difference in defragging a SSD vs a HDD.

With HDDs the OS knows where the data on the HDD. Defrag programs assume that LBA (Logical Block Addresses) are fixed to a specific physical point on the hard disk. for example, LBA=1 is next to LBA=2, which is in turn next to LBA=3, thus when you defrag, it moves adjusts the files locations on the disk's platters where they can be read sequentially to increase the speeds. This is not the case for SSDs as LBAs for flash pages change based on its wear leveling algorithm.

For SSDs since they have flash memory and have a controller that takes care of wear leveling, when you defrag, it is a waste of writes to the drive on the drive, the OS thinks it knows where it is, but it really does not. It simply tells the SSD to read and write the data over in a certain location, but the controller of the SSD actually tells the data where to go. So, the OS does not know how data is being mapped on the SSD, the controller maintains the OS's understanding of the LBA but keeps it own internal LBA map.

Fragmentation is not going to hurt a SSD's speed. As a matter of fact SSDs fragment data on purpose to increase performance through parallel access, fragmentation is a requirement for maximum SSD performance. SSD controllers use multiple channels (typically 8-10) to improve performance (like RAID 0). Fragmenting data helps to ensure best performance. Even if a file is stored in sequential blocks according to its LBA address (ie. the file is not fragmented according to the OS/defrag program), it might be sprawled across several flash chips.


Quick vs. Full Formatting:
Here I explain what the difference b/w a quick and full format are and why you should only quick format your SSD.

• A quick format - is a formatting option that creates a new file table on a hard disk but does not fully overwrite or erase the disk. Quick formatting erases/rewites the FT (File Table) of the File System partition. So basically quick formatting just erases/rewrites anew what is essentially a directory that tells the operating system where files are and what spaces are free to write new data on.
  
  
• A full format - is a formatting option that creates a new file table on a hard disk, but does not fully overwrite and erase the disk as well. A full format erases/rewrites the FT (File Table) of the File System partition and runs chkdsk. Chkdsk.exe is a command-line tool that checks volumes for problems. The tool then tries to repair any that it finds. For example, Chkdsk can repair problems related to bad sectors, lost clusters, cross-linked files, and directory errors. Chkdsk does one pass of writing zero's to the drive to ensure that the sectors are working properly. But the zero's are also rewritten with the previous 1 or 0. This is why full formats take so much longer. So basically a full format is quick format + Chkdsk.
  
  
• You don't need to run chckdsk on your drive b/c all it does is check for bad sectors and checks file system integrity assuming that the LBA's are going to be located in a specific place, but just as I said with defraging, the controller will only know what LBA is what and the program will not, so it is useless. It is not "good" for your SSD because all it does is cause add wear to the memory cells when you don't need it to. So in all only quick format your SSD.

Erasing all the data on the SSD:
It is not safe to use DBAN Nuke or similar on SSDs. First, it's not good for the drive, and second, it wouldn't work properly anyway. Not good for the drive because it writes to the drive too many times. Wouldn't work properly because just like the OS, DBan cannot control where it writes to on the drive. The SSD's controller is responsible for that, and due to wear leveling algorithms, wouldn't get you the intended results. With an SSD, all you need is to perform a "secure erase".

• Secure Erase - Secure Erase is where the SSD controller issues the ATA Securiy Erase Unit command that applies a voltage spike at a specific voltage to all of the NAND simultaneously flushing the stored electrons from the flash memory cells, thus cleaning the NAND. This in turn resets all the NAND cells on the SSD and leaves the drive's data in an unrecoverable state and at factory speeds.
  
  
• How to: Secure Erase your Solid State Drive (SSD) with Parted Magic: (link)

Recoding Media
Also, it is not recommended that you use a SSD for Video recording. Due to the nature of NAND memory, limited P/E cycles, and garbage collection the write speeds of the drive will suffer significantly after constant use. A HDD or HDD array would be a much better choice as a recording media.

Why listen to me?
I'm going to focus on SATA SSDs as that is the majority of the consumer SSD market. I have done countless hours of my own research over this topic and have nearly a full understanding of what is ideal. I am not the say all and end all, I am just stating what I think. These suggestions will be off of current SSDs and will not consider older ones which are replaced by newer models.

The difference in real world between all current gen SSDs is so minute that it doesn't matter if a benchmark says one is faster than another. Even the difference between SSDs on SATA 2 vs having it on SATA 3 and even having 2 in a RAID 0 array is going to be a insignificant change for the average user, please keep that in mind...even when I use performance tests to validate one over the other in benchmarks.

You don't need the newest, most expensive, and highest-rated SSD. If you have the money for a platform upgrade, there are certainly are some gains from upgrading to a Native SATA 6Gb/s-capable motherboard and the best solid-state drive. However, on a tighter budget buying the SSD that everyone says is the fastest isn't as important as buying an SSD you can afford, ESPECIALLY when replacing a hard disk as your system drive. SATA 6 Gb/s only allows a wider bandwidth, aka, higher max seq speeds, access times and 4k reads/writes will be pretty much the same on SATA 6Gb/s as on 3Gb/s ports. So you will hardly notice a difference b/w either in daily use 99% of the time. (Read this!)

Also, almost all newer (better) SSDs are SATA 3, so it doesn't even matter in deciding on one vs another anymore.

Now when you want to decide on a SSD look at size first. Then look at the overall choices and narrow down by features, user reliability, company support and warranty, speed, and price.

I usually suggest you wait for a sale on the drive you want or get what ever is a good price.

*If you ask me which one would be the best for gaming? I will laugh.
Honestly, there is almost no difference b/w these SSDs in real world use. 100%, no lie. You are fine with any one of my recommended. If you want go look at reviews and see what caters better to you. Some are cheaper than others b/c they have slower asynchronous NAND, while others are just cheap b/c they are just on sale or the store needs to move stock, so just have an eye out for that.


Capacity:
Okay, this is how you should start off your decision on what drive you are going to purchase. The bigger the drive the the better. One thing to notice is that with most 60/64GB SSDs is that their 120/128GB and larger counterparts usually have twice the lifespan. You get more space for wear leveling, you get longer life spans due to usually more NAND chips used, and performance usually scales with size as well. If you are wondering whether to get 1 large SSD or 2 or more smaller ones and RAID 0 them or just leave them as separate drives I suggest you simply get the single larger drive.

• Smallish boot drive: (~64GB) - With a 64GB drive you get ~59.6GB of formatted space. With a 60GB drive you get ~55.9GB of space. If you want to install the OS, all the programs that you want, and a game or two, then a 60/64 GB SSD will do.
  
  
• Medium sized boot drive: (~128GB) - With a 128GB drive you get ~119.24GB of formatted space. With a 120GB drive you get ~111.79GB of space. If you want to install the OS, all the programs that you want, a few games and such I would recommend a 120/128GB SSD at least.
  
  
• Large boot drive: (~256GB+) - If you want to have Steam or most/all of your games or other large items on your SSD then I would recommend at least a 240/256 GB SSD.

SandForce SSDs:
SandForce drives aren't known to be the most reliable drives on the market due to many issues with their firmware and support. But, with the latest firmware issues have gone down drastically and since LSI has purchased SandForce there improvements in support.

Intel SandForce SSDs have better non-buggy firmware and are more highly recommended.

I will help you understand which are better than the others. Here we are focusing on the NAND the drive uses and the type of data it will be handling. There are two types of data that your drive processes, they are compressible and incompressible. Depending on what you use your SSD for will help determine which SSD you want.

Compressible data - Data that can be compressed into a smaller size such as say a word document.

Incompressible - Data that can not be compressed into a smaller size such as say videos, music, and pictures.

Now for your operating system and programs and such you will have a mix of both types of data. Almost all data is compressible as well as incompressible to some degree. On average programs and the OS files are ~50% of each. So, it is beneficial to have a drive that handles compressible as well as incompressible data faster. You want a drive with Synchronous or Toggle NAND for the best performance, not Asynchronous. For a few dollars more, a SSD with Synchronous or Toggle NAND will likely deliver a much better experience. We are on Overclock.net, who doesn't want the fastest and best, especially for the same or better price?


My Suggested SSDs: No specific order...

• Mixed controllers with Toggle or Synchronous NAND:
  • Corsair Neutron (5yr warranty) / (Synchronous MLC NAND)
  • Corsair Neutron Series GTX (5yr warranty) / (Toggle MLC NAND)
  • Crucial M4 (3yr warranty) / (Synchronous MLC NAND)
  • Crucial M500 (3yr warranty) / (Synchronous MLC NAND)
  • OCZ Vertex 4 (5yr warranty) / (Synchronous MLC NAND)
  • OCZ Vector (5yr warranty) / (Synchronous MLC NAND)
  • Plextor M5 Pro (5yr warranty) / (Toggle MLC NAND)
  • Plextor M5S (3yr warranty) / (Synchronous MLC NAND)
  • Samsung 840 Pro (5yr warranty) / (Toggle MLC NAND)
  • Samsung 830 (3yr warranty) / (Toggle MLC NAND)
  • Samsung 840 (3yr warranty) / (Toggle TLC NAND)
  • High end SandForce preferably with Toggle NAND.
  
  
• High end SandForce - Anything with Synchronous or Toggle mode NAND. These are a lot faster with incompressible data. Please look into one of these drives before you consider a asynchronous SandForce drive, it would be a waste of $ to buy a asynchronous drive when you can get something with Toggle or Synchronous NAND for a similar or lower price imo.
  
  Toggle NAND SandForce:
  • Corsair Force Series GS (3yr warranty)
  • Mushkin Chronos Deluxe (3yr warranty)
  • OCZ Vertex 3 Max IOPS (3yr warranty)
  • Sandisk Extreme (3yr warranty)
  • Transcend SSD720 (3yr warranty)
  
  Synchronous NAND SandForce:
  • ADATA XPG SX900 (3yr warranty)
  • ADATA S511 (3yr warranty)
  • Corsair Force Series GT (3yr warranty)
  • Intel 520 (5yr warranty)
  • Intel 335 (3yr warranty)
  • Intel 330 (3yr warranty)
  • Kingston HyperX (5yr warranty)
  • Kingston HyperX 3K (3yr warranty)
  • Mushkin Chronos MX (3yr warranty)
  • PNY XLR8 Pro (3yr warranty + 2 with registration)
  • PNY XLR8
  • PNY Prevail Elite (5yr warranty) / (eMLC NAND)
  • PNY Prevail
  • OCZ Vertex 3 (3yr warranty)
  
  
• Low end SandForce - Anything with Asynchronous NAND. These are a lot slower with incompressible data than their higher-end brothers. Usually I'd recommend these to people who are an a very tight budget or those who want a cheap SSD for storage.
  
  Asynchronous:
  • ADATA S510
  • Corsair Force Series 3
  • EDGE Boost Pro 120GB
  • G.SKILL Phoenix III
  • Kingston SSDNow V+ 200
  • Mach Xtreme DS Turbo
  • Mushkin Chronos
  • OCZ Agility 3
  • OCZ Solid 3
  • OWC Mercury Electra 6G
  • Patriot Pyro
  • Super Talent TeraDrive CT3
  
  
  SSD database and reviews:
  SSD Data Base
  SSD Reviews Thread
  
  
  
  
  Click here to go back to the top

How do you properly install Windows 8?
Simply follow my install guide: Sean's Windows 8 Install & Optimization Guide for SSDs & HDDs


How do you properly install Windows 7?
Simply follow my install guide: Sean's Windows 7 Install & Optimization Guide for SSDs & HDDs


How do you physically install one in your system?
Just like any other drive you have ever put in your computer. You may need a 2.5" to 3.5" adapter to fit it in your PC's normal drive bays, but that is not needed. Here is the cool thing though, since SSDs don't have moving parts you can just stick them where ever you like. For example, you can take some Velcro and stick one to the side of your case, you can hide them in the back of the mobo, you can even just let them dangle in the middle of your PC if you like.

Examples: (link)

Laptops & SSDs:
Usually due to hardware limitations and power saving features in laptops SSDs will perform slightly slower than in their desktop counterparts. But the difference is usually only seen in benchmarks.

SATA Cables:
Whether they are plain old SATA, SATA 2, or SATA 3 cables they all have the same though put. The only difference b/w any SATA cable is the quality of the material used in the cable. (Read the testing results and more info here)

SATA vs SATA 2 vs SATA 3
For the most part all SATA connections are forward and backwards compatible. Only very few old chip sets with SATA connections cannot accept newer SATA 3 devices.

Native vs. Non-Native SATA ports:
Native Ports are better than the non-native SATA ports in your mobo.


Add-on SATA 6Gb/s controllers vs Native SATA 3Gb/s:
I suggest you use the onboard SATA instead of using a PCIe card. PCIe cards add latency and are not really worth it just for SATA 3. You will hardly even notice the difference in use b/w SATA 6Gb/s and SATA 3Gb/s honestly, even 2 SSDs in RAID 0 there is hardly a difference in real world use.

If you do end up getting a a card you need a card that is at least PCIe 2.0 x4 and it needs to be bootable if you want it for the OS drive. Like this: (link)

Also, with a add-on card your boot times will be lengthened, stuttering, and other issues can occur as well.

Intel vs. AMD SATA:
Most of the time SSDs will deliver higher scores in benchmarks on Intel systems than on AMD systems. One thing to remember when comparing scores is to make sure the system you are comparing is similar to yours.

Types of SATA modes:
These are the dfferentways you can set up your SATA mode in the BIOS/UEFI.

• IDE - Old, slower, it is simply a compatibility mode. TRIM does work in IDE mode.
  
• AHCI - AHCI stands for Advanced Host Controller Interface. It makes Native Command Queuing (NCQ) along with hot-plugging or hot swapping through SATA Serial-ATA host controllers possible. NCQ is one of the important features of AHCI for SSDs. SSDs can process requests faster than HDDs. It can process so fast that the SSD could end up waiting for work. NCQ allows the OS/controller to request up to 32 simultaneous requests at once. So you basically get more performance from your drive over older IDE mode.
  
• RAID - RAID stands for Redundant Array of Inexpensive Disks. It is a means by which your PC uses multiple disks as if they were one, either to increase performance, safeguard against disk failures, or both. RAID mode has all the advantages of AHCI mode. There are four main factors of a RAID setup: striping, which spreads data across multiple drives, mirroring, which copies the data to more than one disk, space efficiency, which is how much of the total space is available to use, and fault tolerance, which is a measure of how well protected the RAID array is against disk failure.
  
  
  RAID 0:
  There's no real benefit in RAID0 SSD for most people since it just boost sequential performance. You generally do not need to load massively large files into memory nor have another storage device fast enough to transfer from/to.
  
  Pros:

  • 2X faster sequential reads/writes of the slowest drive (not really noticeable with SSDs).
  • 2X space of the smallest drive.

  
  Cons:

  • No TRIM support for SSDs part of a RAID 0 array for the most part. TRIM only works for RAID 0 arrays on Intel 7 series chipset motherboards (excluding x79) with the 11.2 RST driver and above. (link)
  • RAID 0 only improves sequential performance which is generally not that useful and it also almost doubles your failure rate. (1 drive goes the array is lost and all data is gone, you need to have a backup of all the data on the array in case of a failure)
  • Slightly slower boot time (The RAID controller needs to initialized after the BIOS does and that adds time to your boot time, usually 3-5 seconds slower)
  
  Additional Notes:
  • If you have a AMD RAID array make sure that you can NCQ enabled in RAIDXpert. If not you may lose performance that you can easily gain back.

Links to OCN member benchmarks: (Click to show)
Benchmarking:
Although benchmarks are nice to run to see the performance of your drive, you can over bench an SSD. Benchmarks write a huge amount of data to the SSD. You can often see a huge difference (slower performance) in the same drive, if you run benchmark after benchmark. Part of the reason for this, is that the drive may not have had enough time to "clean up" the data that was written to the drive in the previous benchmark. Also, you are performing a huge amount of unnecessary writes to the drive, basically to see the same results. My recommendation, is to try not to run benchmarks more than once a month.

Download Benchmarks from here:

• AS SSD
• Anvil Storage Utilities
• ATTO Disk Benchmark

How to set up the benches to post:

1. Make a new post in this buyers guide thread dedicated to only the benches you post. Then I can just link it to the SSD on the list.
2. Follow the layout below

---

SSD test info:

• SSD: Corsair Performance Pro
• Capacity: 128GB
• Interface: Intel SATA 6Gb/s

Anvil storage


AS SSD (All three tests)


ATTO

Sean's Premium Threads:



SSD Section:


Speed up your SSD in a laptop:
How To Improve SSD performance on Intel Series 4, 5 and 965 chipsets (Stamatisx Tweak)
How To Improve SSD performance on Intel Series 4, 5, 965 Chipsets (JJB Tweak)
Laptops w. Intel Series 5 chipset can not take full advantage of fast SSDs

Non-OCN:
http://arstechnica.com/information-technology/2012/06/inside-the-ssd-revolution-how-solid-state-disks-really-work/
http://techgage.com/article/too_trim_when_ssd_data_recovery_is_impossible/1