Forgive me if there already is a suitable thread to post in - brief search didn't reveal any treasure

I've got fairly simple question:

Has anyone around here experienced any performance increase from running in AHCI mode? I mean, from what I've read here and there, it's mostly just subjective feeling of "faster", but has anyone really seen at least a little obvious increase?

Second part of the question is CPU usage. Is it higher/lower/same as in IDE mode?

I got me Samsung Spinpoint F1 (HD103UJ) disk several weeks ago and I was thinking...

Thanks.

Yes, AHCI mode is faster - not a feeling. When I was experimenting with BartPE, I made a lot of ISO's and I noticed significantly faster speed in AHCI mode than standard IDE mode.

I would think CPU usage is higher as disk activity and CPU are not always tied together. I'm not so certain however.

Actually there is no "speed difference" in data transfer.

http://en.wikipedia.org/wiki/Serial_ATA

As their standard interface, SATA controllers use the Advanced Host Controller Interface (AHCI), which allows advanced features of SATA such as hot plug and Native Command Queuing (NCQ). If AHCI is not enabled by the motherboard and chipset, SATA controllers typically operate in "IDE emulation" mode which does not allow features of devices to be accessed if the ATA/IDE standard does not support them. Windows device drivers that are labeled as SATA are usually running in IDE emulation mode unless they explicitly state that they are AHCI. While the drivers included with Windows XP do not support AHCI, AHCI has been implemented by proprietary device drivers.[1] Windows Vista[2] and Linux with kernel version 2.6.19 onward [3] have native support for AHCI.

BUT NCQ - only available in AHCI mode:

http://en.wikipedia.org/wiki/Native_Command_Queuing

can make the difference in "real" speed.

In other words, using a drive WITHOUT NCQ, there won't be differences, if using newish drives WITH NCQ, there will be a speed increase (and lower CPU overhead).

The size of the Queue (bigger for SCSI drives) accounts also for some of the reasons why some of them are being faster than SATA.

jaclaz

lower CPU usage is alwaays good

And I would say there should be SOME difference at least because of emulation and no emulation.

will give it a shot anyway!

well thanks for clarification jaclaz. yes my drive is ncq and hence i observed the speed increase.

Weird stuff happening! It works BUT I randomly get BSOD with message about iastor.sys or whatever the name of the driver is. I don't like it at all...

About what SATA controller (ICR9 or 10 for example) are we talking about here?

ICH9R. The board is GigaByte EP35-DS4. I downloaded the latest driver from Intel.

Well well... I flashed new BIOS and now my HDD cannot be found anymore. The AHCI BIOS gives me this error message for the disk - "device init parameter failed". What the hell is this?? If I switch to IDE mode its ok, but since I got Windows installed in AHCI, I can't boot anyway. What kinda freaky error is that and why is it happening? :-O

Can someone translate this for me please?

http://62.109.81.232/cgi-bin/sbb/sbb.cgi?&...amp;beitrag=752

Can someone translate this for me please?

http://62.109.81.232/cgi-bin/sbb/sbb.cgi?&...amp;beitrag=752

Google translate is enough to understand that the OP had a problem with BIOS update F6c and had to revert to F6a to solve the problem.

jaclaz

Well well... I flashed new BIOS and now my HDD cannot be found anymore. The AHCI BIOS gives me this error message for the disk - "device init parameter failed". What the hell is this?? If I switch to IDE mode its ok, but since I got Windows installed in AHCI, I can't boot anyway. What kinda freaky error is that and why is it happening? :-O

I read somewhere on this forum that the newest BIOS update (for Gigabyte) removed that functionality altogether so if you installed XP, you're screwed. AHCI only works with Vista according to Gigabyte manual.

Well, only that I couldn't even boot from CD in IDE mode too... Totally weird behavior. Plus I got an error straight at the AHCI BIOS boot screen. Something fishy about the whole BIOS.

I had to revert to F5.. Sadly I couldn't find a link to 6a.

Anyway, hoping they will fix this.

**** releases with absoluetely no changelogs!

See if any of the links here help:

http://www.giga-byte.it/download/mb/bios/20332/

If not, try googling for:

motherboard_bios_ga-ep35-ds4_f6a.exe

jaclaz

I'll upload a benchmark next two days. I'm currently testing with a windows xp unattended setup and thus i've to reinstall the pc very often. zapping between the bios settings isn't a problem

Motherboard: Asus Rampage Formula (Intel X48 / Intel ICH9R)

Harddisk: Seagate Barracuda 7200.11 500GB sATA2 ST3500320AS (PDF)

Regarding this topic, Intel has nice informations about AHCI at http://www.intel.com/technology/serialata/ahci.htm including specifications. Benchmark will be done with HD-Tach.