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[Official] Samsung SSD750/830/840/850 Owners Club - Page 145

post #1441 of 5733
Quote:
Originally Posted by ucode View Post

It's not about accessing a tiny file, it's about how windows works with x86 i.e. by using a 4kB page size and very relevant if you are not using any prefetch.

Still only relevant if somehow you are only using a single 4kb page. That's why there are tests for queue depth. The only real weakness would be if you had a limited amount of ram where you were actually running pages directly from the disk or page file and they happened to be shared pages between multiple programs or processes. But with the current availability of RAM and how small most shared pages actually are, that should be an easily avoidable issue.

Sure, there are performance increases to be had in single 4k thread performance, but I would much prefer a drive that can hit 500+MB/s at a high queue depth (4-16+) and only manages 20-30 for a single 4k block than a drive than does 100MB/s for a single 4k thread, but can only hit 200MB/s for larger queue depths.

Now I understand that with SSDs and most general uses, you rarely will exceed a QD of like 5-10. But when your queue is shorter than that, you don't really NEED that speed. The reason I say this is that 1 4k read is 4096 bytes.

4096 bytes = 0.00390625MB

My 840 Pro under a SINGLE 4k thread manages about:

30MB/s = 0.03MB per millisecond

This means that if the drive is under such a load that it NEVER processes more than one block at a time it can still do:

10 IO/ms or 7680IOPS

Now admittedly 1 MS is a very long time for a CPU, but it is imperceptible to your or me. Regardless, it has nothing to do with why an SSD seems so fast. A HDD can do a 4K transfer (NOT READs) just as fast (if not faster) as an SSD. What makes an HDD so slow is Seek Time, and it's inability perform more than 1 read at a time without a huge performance hit. If you are using an HDD, and you try to read 2 files that are in different parts of the drive at once, it has 2 options, it can either alternate between the two file locations which is horrible for performance as a seek is required every time, or you can just do them in sequence with a seek in the middle. Now which is done is largely dependent on priority and filesize, but neither is a good option.

The real problem comes with multi tasking. Say you are hosting a file server on your machine and someone in another room is streaming a bluray iso off your drive. Then you decide you want to play a game on the same drive. In theory an operating system could be designed in such a way that it would never affect an ongoing read operation, but that's not the case, so rather than waiting for the video to finish its latest buffer session, it's going to immediately seek the drive and while the gaps in seeking wouldn't be hugely detrimental to the random reads for your game (other than just making it load slower) it would cause a very clear and obnoxious impact to the playback of the video that is being streamed.

An SSD doesn't have this problem. From what I understand an SSD is essentially a tiny raid array across 8-16 DIMMs. There are 2 ways this improves performance, the first is that if the files in question are located on different DIMMs they can be read at the same time. The second is that if they happen to both be present on the same DIMM, it can alternate between reads for the 2 files with no seek time in the middle, so rather than waiting milliseconds to alternate block to block, you are simply halving your random access read time between 2 operations.

This is where your controller and firmware become extremely important. Since at least in theory, they should be balancing commonly accessed blocks across your NAND, so that you don't end up with 20 reads on 1 NAND and 15 inactive ones. Essentially the Controller is there to cover up the limited speed of a single DIMM's read.

The biggest benefit of significantly increasing single thread 4k speed would be improved endurance of a drive as there would be less need to load balance it.

I do think eventually as NAND prices come down and single die sizes increase, we will start to see SSDs that are built more like RAID 10 than RAID 0, but that's largely irrelevant for now.
Edited by Amnesia1187 - 12/26/12 at 5:48am
post #1442 of 5733
So what was the final consensus on using cloning software to copy OS from my old SSD to my new one?

I had some people saying yes and others saying no. If I need to use a specific software, which one is the best if Norton Ghost in SSD Magician won't do it correctly?
post #1443 of 5733
Quote:
Originally Posted by NCSUZoSo View Post

So what was the final consensus on using cloning software to copy OS from my old SSD to my new one?

I had some people saying yes and others saying no. If I need to use a specific software, which one is the best if Norton Ghost in SSD Magician won't do it correctly?
Doesn't make a difference if you clone or reinstall.

Some softwares to use here: www.overclock.net/t/1227835/how-to-disk-and-partition-cloning-backup-restoration-migration
post #1444 of 5733
Hi Everyone

Snagged a 250gb Samsung 840 today in Amazon's after-Christmas sale. It is my very first SSD.

I am just wondering if anyone could give me some general advice on SSDs or point me in the right direction for basic, useful information.

I know I will need to do a fresh install of win7 and only install the most commonly used programs onto the SSD. Don't defrag an SSD ever, I've come across that tip. Enable TRIM. Use my two 1tb HDDs only for personal files and all other programs.

Anything else I should know? I came across a forum discussion about % of drive you should leave unused for optimal performance. What is that all about? Particulars like that would be really helpful to know.

Thanks all, I really appreciate any and all advice I can get.
post #1445 of 5733
post #1446 of 5733
Quote:

exactly what I need. cheers! thumb.gif

if there are any specifics that are particularly important, please don't hesitate to share

EDIT: I ran through the basics on Sean's thread. From what I can gather, what I was describing in my previous post is called overprovisioning. I now understand why other people suggested leaving a % free. However, accordnig to Sean the manufacturers compensate for this by building this free % space into the drive itself. For normal usage, is this built-in overprovisioning enough or should I also opt to leave a certain amount free at all times?
Edited by bam06005 - 12/26/12 at 1:03pm
post #1447 of 5733
With a 250Gb drive I really don't think you are going to have to worry about that, but leave at least 5-10GB free, just like you would on any HD.

Windows 7 is optimized already for SSDs and the included Samsung SSD Magician will have any other tweak options you will need basically.

When I first went to a SSD I worried about so many things that either didn't make a difference or didn't matter in the long run.

One tip I can give you is to move your browser cache on to your RAM: http://lifehacker.com/5687850/speed-up-firefox-by-moving-your-cache-to-ram-no-ram-disk-required

Also if you have enough RAM, moving your Page File and Temporary Files to your RAM helps unnecessary writes/reads. My ASRock Z77 Extreme3 does this through it's own software with XFast RAM or I'd have a link for you.
Edited by NCSUZoSo - 12/26/12 at 1:19pm
post #1448 of 5733
Quote:
Originally Posted by Liranan View Post

How does EaseUS compare with Acronis?

First let me re-state the old adage; "Opinions are like *******s, everyone has one.". Here is my opinion in response to your question. I am emphasizing this is an opinion because I know many knowledgeable people disagree with me.

I do not like Acronis because it must be installed under W7, taking up too much precious SSD space. It also installs some resource robbing services that are loaded every time W7 starts. It is a complex piece of software that does many things I will never use. I just want to be able to easily and reliably make a plug and play clone every few weeks, nothing more. I perceive it as bloatware and want nothing to do with it.

EaseUS, on the other hand, installs directly to a USB memory device and also boots from the USB memory device. It takes up no SSD space and no services running in the background. It is not loaded with unnecessary features (at least unnecessary for my needs) and is simple and reliable to use. EaseUS is also free, Acronis is not.

What it comes down to is a personal choice as they are two very different products, even though they do some of the same things. I, obviously, do not like Acronis or any of the other backup packages that require a W7 installation. But, please consider that there are a lot of knowledgeable people that use these products and are very happy with them.

I hope this helps.
post #1449 of 5733
Quote:

Just a heads up to Sean Webster, that sticky is really freaking hard to notice when its the same color as the background. I actually went looking for the SSD optimizations thread a while back and couldn't find it for about 10 minutes until I realized what I thought was a banner was actually a link to a sticky collection. Food for thought.
post #1450 of 5733
Quote:
Originally Posted by NCSUZoSo View Post

With a 250Gb drive I really don't think you are going to have to worry about that, but leave at least 5-10GB free, just like you would on any HD.
Windows 7 is optimized already for SSDs and the included Samsung SSD Magician will have any other tweak options you will need basically.
When I first went to a SSD I worried about so many things that either didn't make a difference or didn't matter in the long run.
One tip I can give you is to move your browser cache on to your RAM: http://lifehacker.com/5687850/speed-up-firefox-by-moving-your-cache-to-ram-no-ram-disk-required
Also if you have enough RAM, moving your Page File and Temporary Files to your RAM helps unnecessary writes/reads. My ASRock Z77 Extreme3 does this through it's own software with XFast RAM or I'd have a link for you.

Thanks for the advice.

Question - how does setting browser cache help the SSD? Is that just a small tweak to reduce browser build-up on the SSD?

I will see if I can't figure out how to do that with the Page and Temp files!
Edited by bam06005 - 12/26/12 at 3:43pm
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