SM951 AHCI 512GB performance in Win7

ArvUK wrote: Hi all,   I have a question about my 512GB SM951 AHCI performance.  I'm not seeing the expected numbers from the link below.   http://tssdr1.thessdreview1.netdna-cdn.com/wp-content/uploads/2015/05/Samsung-SM951-512GB-AS-SSD.png   Most are close except for 4K-64Thrd.  My score is just over half that number, with overall score in the 1400's and I'm struggling to find out why.  This is in Windows 7 Pro SP1 with all current patches applied.   Hardware: ASRock X99-WS (UEFI 3.10), CSM enabled Intel Xeon 2620 v3 2.4GHz Six-core CPU 64 GB (4 x 16GB) M393A2G40DB1-CRC - 16GB Samsung DDR4-2400Mhz LP ECC REG Server Memory NVidia NVS 310 Dual Displayport video card 512GB SM951 AHCI - 75GB Windows 7 Pro SP1 partition (UEFI), 120GB Windows Server 2012 R2 partition (UEFI)   I'm running Windows Server 2012 R2 for my test lab running SQL 2014 and Microsoft Identity Manager 2016.   In that image link it shows StoreAHCI.sys being used.  Mine shows MSAHCI which is the MS driver.  How do I switch to the Intel driver?  What are the steps to do that?

Actually, storahci.sys is a Microsoft driver. It seems to be little more than the msahci.sys driver renamed.

This is the driver details for the IDE ATA/ATAPI Controller entry, the Standard AHCI Controller entry for my SM951, from Device Manager in Windows 10:



Note the date of the driver, 2006, which is of msahci vintage. I believe MSoft changed to storahci in Windows 8 or 8.1. Interesting they did not change it in Server 2012 R2, which may tell us this "change" is merely cosmetic. Also, at least one PC hardware review website considers Server 2012 to have the best IO performance of any Windows product.

I understand the name storahci implies an Intel driver, the "stor" in it. While Intel could be the source, usually they keep credit for their work, but who knows?

If we check the Intel AHCI and RAID drivers from their "F6flpy-x64" driver download package, the driver names are different:



This would be the driver file package you would use to change to the Intel AHCI driver. Actually, try to change would be the more accurate description.

Many SM951 users attempted to change to the Intel AHCI driver, but that normally fails. I recall one SM951 user finally succeeded, but it was a convoluted procedure, and the difference in performance was minimal to none.

To update the AHCI driver, you open the Device Manager Properties of the IDE ATA/ATAPI Controller entry, and then the Standard AHCI Controller entry. Click the Driver tab, and then click the Update Driver button. From there you must have the AHCI driver file folder on the PC, and select the Browse option for driver software. Follow the prompts to complete the update.

Normally the result is Windows decides you have the best driver installed now, and the update fails.

SSD benchmark results can be lower than expected for a few reasons. CPU and Chipset power saving options being enabled cause latency that reduces performance. Then there is the new, fresh out of box SSD benchmark result, compared to the same SSD being used as an OS drive. The OS drive SSD will always score lower than a non-OS drive, and new vs used SSD will reduce it further. The amount of free space on the SSD also can make a difference. Who knows what the state of the SM951 in your AS SSD screenshot was, a new empty drive, or OS drive? Your SM951 is no doubt well into its "steady state" performance phase, meaning it is not a fresh SSD with plenty of unused free space.

Sorry but must ask, you are sure you have the AHCI version of the SM951, and not the NVMe version? The AHCI version has "MZHPV" in the model name.

The AS SSD 4K-64Thrd test is very difficult, and at twice the standard AHCI queue depth, 64 vs 32. Any decent SSD will never have more than four outstanding IO requests in the queue, and a PCIe SSD will rarely have two. Your usage situation may not be that of a standard PC, is you are running database requests on it, as well as serving as the OS drive. That may explain your performance situation.

parsec wrote: I believe MSoft changed to storahci in Windows 8 or 8.1. Interesting they did not change it in Server 2012 R2,

They did change it in 2012 R2

https://msdn.microsoft.com/en-us/library/windows/desktop/hh848066(v=vs.85).aspx

This laptop I'm typing on could I guess support a 1 CPU VM, yet I'm not foolishly going to attempt it. Bring it to its knees it would with an 2012 R2 VM.

I have a hunch that what the OP is seeing is solely the way a VM might configure that driver, being virtualized as is is.