AHCI still not fixed???

Want to try a nvme driver?
OpenFabrics: Windows NVM Express Files

not sure if this would help me, as i have the ahci version of the drive. i'll have to do some more research. but thanks for the link.

STEVAE said:

not sure if this would help me, as i have the ahci version of the drive. i'll have to do some more research. but thanks for the link.

Hi all, first post here it’s an amazing Forum with great participants and a very informative one.

You can try the latest IRST 13.6.0.1002 driver, or an old one, the IRST 13.2.4.1000, used by Anandtech’s review of this drive: http://www.anandtech.com/show/8979/s...12-gb-review/2

Both drivers (available in Intel Download Center) should give SM 951 much better performance than native Microsoft drivers, as it’s usual with almost all AHCI drives, after all the AHCI technical standard was developed by Intel.

Just my two cents...
Cheers

Mystere said:

What i'm reading is that AHCI is basically a dead-end for PCIe devices, and that a new controller type called NVMe (or NVMHCI) is what will be used to make these drives perform well. However, you need to have a drive designed for NVMe.

I'm not really finding any information on improve AHCI drivers... The problem stems from the limitations of the AHCI protocol itself, which you can read about here:

NVM Express - Wikipedia, the free encyclopedia

Specifically this:

	AHCI	NVMe
Maximum queue depth	1 command queue; 32 commands per queue	65536 queues; 65536 commands per queue
Uncacheable register accesses (2000 cycles each)	6 per non-queued command; 9 per queued command	2 per command
MSI-X and interrupt steering	single interrupt; no steering	2048 MSI-X interrupts
Parallelism and multiple threads	requires synchronization lock to issue a command	no locking
Efficiency for 4 KB commands	command parameters require two serialized host DRAM fetches	gets command parameters in one 64 Bytes fetch

SATA (AHCI) will not be a dead end for quite a while. SATA disks will continue to be more cost effective than flash or phase change storage, which is what NVMe is for. You cant plug a SATA or SAS hard disk drive into NVMe. Saying AHCI is dead because of NVMe is better is silly as they are apples to oranges.

Now SAS may replace SATA, but SAS drives are generally more expensive than SATA. SATA drives are compatible with SAS, but that requires the SATA protocol gets tunneled through SAS (STP), and the drive still appears as SATA/AHCI to the OS.

squawker said:

Hi all, first post here it’s an amazing Forum with great participants and a very informative one.

You can try the latest IRST 13.6.0.1002 driver, or an old one, the IRST 13.2.4.1000, used by Anandtech’s review of this drive: http://www.anandtech.com/show/8979/s...12-gb-review/2

Both drivers (available in Intel Download Center) should give SM 951 much better performance than native Microsoft drivers, as it’s usual with almost all AHCI drives, after all the AHCI technical standard was developed by Intel.

Just my two cents...
Cheers

yeah, i'm already running 13.6.0.1002. it's a good comment though, as you're right, intel is responsible for ahci. thanks!

Geneo said:

SATA (AHCI) will not be a dead end for quite a while.

I was quite clear about it being a dead end for PCIe devices (as in, devices you plug directly into PCI express sockets), not SATA.

I can confirm that this problem exists in Windows 10. I have an Asus X99 Deluxe mobo with the SM951 AHCI. Under Windows 7 i was able to get 2200MB/s read. Now i am not able to get over 1550MB/s. I have tried the ssd in the M2 slot and on the hyper-card. Makes no difference. Installed IRST_V14_5_0_1081_WHQL. Makes also no difference.