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Samsung 830: SATA II + IDE vs. SATA III + ACHI (Difference?) - Page 2

post #11 of 13
Some clarifications for you.

There is a BIG difference between IDE and AHCI mode, which mainly means which SATA driver program is being used. AHCI mode (or driver) has NCQ, the Native Command Queuing function, which IDE does not have. In IDE, one I/O request is sent to a drive at a time. With NCQ, up to 32 I/O requests are sent to a drive at once.

Imagine Windows booting, it needs to load all kinds of files, programs, data, etc., 100's of them. The majority must be read from disk. Say you have 100 I/O requests waiting. An IDE driver reads one of the 100 I/O requests, sends it to the drive, and waits for the drive to complete the request, and then continues with the next I/O request. An AHCI driver sees 100 I/O requests, reads 32 of them, and sends them all to the drive at once. None of the overhead of waiting for one command to complete before sending another.

A SSD can process multiple I/O requests at the same time, as well as being faster than a HDD (HDDs also use AHCI/NCQ, which speeds them up, but for different reasons.) Imagine a SSD processing one command at a time in IDE mode, a waste of speed. That is clearly shown in the benchmark results. A SATA III SSD used on a SATA II only interface, with AHCI mode, will be faster than a SATA III SSD on a SATA III interface, but in IDE mode.

The Windows DisableDeleteNotify = 0 means that TRIM is enabled in Windows, and is sending TRIM commands to the SSD, via the SATA controller and driver.

The question (and potential problem) is, does the Nvidia driver pass the TRIM command to the SSD? There seems to be some information that the Nvidia driver does not pass the TRIM command, but I've never used one, so I don't know, perhaps Sean or someone else does.

The SATA driver that is installed will have no affect on whether or not Windows sends TRIM commands. Contrary to what some believe, TRIM does work in IDE mode. The real potential issue is does the Nvidia driver pass the TRIM command along to the SSD. The Nvidia driver is old, and MIGHT not recognize the TRIM command, and then MIGHT decide to ignore it, meaning not pass it to the SSD.

The Nvidia driver was developed before Windows 7, the first version to have TRIM, and has not been updated. Programs (a driver is a program of course) are only as "smart" as they have been programmed. Good programming techniques will ignore data that it does not "know" how to deal with, since a fatal error could result. So the Nvidia driver, when encountering the new SATA standard TRIM command, which it MAY not have been programmed to deal with, will react, "unknown command received, don't know what to do, ignore it, continue".

The Nvidia driver is known to do a similar thing when it finds itself connected to a SATA III SSD. All drives have special data that identifies what kind of device it is, so programs can deal with it correctly. Again the Nvidia driver was coded before SATA III existed, and has not been updated.
post #12 of 13
Thread Starter 
^ good post. Thats for the info.

At this point, there doesnt seem much I can do to speed up his PC without him updating his motherboard...so I figure I let it run its course until he starts complaining about his PC not feeling as fast - and then proceed to upgrade his motherboard, so that he is not bottlenecked anymore. A Samsung 830 on SATA II w/ IDE is a sad thing...but replacing in a motherboard will cost money and time...and right now he seems fine with just how much the SDD is already helping him. In due time tho, yes - I think it would be wise to get a SATA III w/ AHCI to really bring his PC to full speed.
Edited by malikq86 - 12/18/12 at 12:55pm
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post #13 of 13
Thanks for you comment. I can't believe ASUS used the Nvidia SATA chipset on that board (cheaper), since the AMD SATA chipset would make all the difference, AHCI mode, good driver, and real support.

Just to review, the only settings you can find for (whatever it is called in that BIOS) SATA configuration, or SATA mode, is IDE or RAID? That should all be in one setting, and AHCI would be there if it was available. That board had a relatively recent BIOS update (January, 2012), but does not mention anything about SATA.

If you can't select AHCI mode on that board, the only potential alternative is RAID. While that may sound strange, both AMD and Intel SATA drivers, when used in RAID mode, treat single, non-RAID volume drives the same as they would in AHCI mode. So for standard, single drives, RAID is equal to AHCI, given AMD or Intel RAID drivers. Can't use them on the Nvidia SATA chip, of course.

But the question is does the the Nvidia RAID mode and driver provide the same AHCI features to single drives, as the AMD and Intel RAID drivers do? I don't know the answer to that question.

As you said earlier, the score of 200+ is AS SSD for that system is much better than any HDD, which normally score at most ~50, usually much less. That is with an AHCI driver used with the HDD, in IDE mode it will be even less. The improvement he will have now will be obvious, but the SSD has potential waiting inside.
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