# How to get AHCI working



## RoutedScripter (Jul 8, 2010)

I have the new WD Caviar black ready for fresh win7 install.

Now , I have P35 southbridge and Intel ICH9R is the chipset , so , and well , I don't find , or should i say , I didn't searched enough , the AHCI preinstall driver for GA-P35-DS4 mobo , it's not in the official gigabyte site , it's only the driver you load up after you install win7 , or how it supposed to work.

Anyways , I get a BSOD if I turn on AHCI while I have no drivers on this "IDE emulation" drive currently. 

Why im into ahci , is maximizing the performance of my HDD , since it's the slowest component , every speed up is well worth it.

I had first experience with RAID install , took me a week to set it up properly , but i have no idea if AHCI needs pre-install , or is that a package for RAID that im misinterpreting , anyways i had seen a lot of these kind of drivers , but my bro where the RAID is , it's a totally different AMD system apart from my intel , i can spoil you the news that AMD has that very well organized and you find what you need on AMD site, everything updated in the Catalyst suite , but on the intel site i just don't figure it out which one is for my mobo since the ICH9R has subnames and i don't know them , i wish the CHIPUTIL35 would work on x64 and it does not , that program identifies model of Intel chipsets , so that's off and I am confused with these 9xx ICH7R / 8R / 9R / 333 / 888 blabla  why the heck so many names , so this is apparently the 3/4 series milestone (5/6 for Core-i) so im confused for WHAT model to look in order to find "win7 x64 AHCI pre-install driver" specifically for ICH9R Chipset , in 3/4 series , with 9xx Southbridge , and whatevermore.


So first i put in the HDD , set the BIOS to AHCI , load Win7 , load pre-install AHCI , install win7 , install Intel AHCI/RAID post install drivers

That sequence right?


EDIT: Lol i just found out , there is no Intel ICH9R AHCI/RAID Preinstall drivers for VISTA and WIN7 , but there is for XP. 

So what now? WIN7 doesn't need it ? I don't know , I didn't even insert the hard drive yet.

My whole WIN7 instal hangs on this thread , since i think ahci can't be done later afaik , so someone help me out.


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## IINexusII (Jul 8, 2010)

is this what you need? http://support.microsoft.com/kb/922976


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## EastCoasthandle (Jul 8, 2010)

Doesn't the AHCI driver have to load and stay as a process for windows?


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## ShRoOmAlIsTiC (Jul 8, 2010)

it does load automatically if you installed windows with ahci set in bios prior to install.  if you set it afterwards then you need to trick it with a reg edit.  check in bios if you have it set to ahci, legacy ide, native ide or raid.  It needs to be ahci.  But if you installed with legacy or native ide then you need a registry hack it with it set in the ide mode then reboot,  set it to ahci in bios then go back into windows.  it will re detecall the drives and ask you to reboot.


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## EastCoasthandle (Jul 8, 2010)

I tried this a long time ago and recall a few other processes in windows once I got it up and running (if I recall correctly).  And for the most part didn't provide any benefit over the IDE option.


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## ShRoOmAlIsTiC (Jul 8, 2010)

the registry location is

HKEY_LOCAL_MACHINE\System\CurrentControlSet\Services\Msahci

go to the value labeled "Start" and set it to 0

so step by step process
1.  Edit the registry - HKEY_LOCAL_MACHINE\System\CurrentControlSet\Services\Msahci,  go to the name Labeled "Start" and set the value to 0
2.  Reboot the system
3.  go into bios and set your sata to ahci mode
4.  go back into windows and let it detect the drives
5.  Let it reboot


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## RoutedScripter (Jul 9, 2010)

Okay , thanks , so that's it ,  XP doesn't have AHCI drivers and does not detect AHCI in bios right ?


I always used native IDE (context is logical, legacy sounds old right?) , since i never knew what the others meant , but i got the picture now.





EastCoasthandle said:


> I tried this a long time ago and recall a few other processes in windows once I got it up and running (if I recall correctly).  And for the most part didn't provide any benefit over the IDE option.



Oh i need demotivationals right now , i see good benefits but in the practice i honestly don't expect much , anyway that's an enthusiastic drive , don't make me like im wasting time , feels bad since i don't have much time really , and oh , im trying it for the first time , i hope something improved over the long years , just hope it will not cause BSODs.

What about the caching and other options , do i get a special AHCI control panel to set some options,  performance wise.

On a side note , should i use 4kb stripe size (or hows called with non-raid setups) , to maximize performance of small-middle files , but with 1 TB HDD , space is not an issue so risking anything for performance is not a big deal.

I also heard there are OS and application issues when it comes so format allocation , very high or low numbers can cause stability issues , right?


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## ShRoOmAlIsTiC (Jul 9, 2010)

yeah xp you would need the f6 ahci drivers for it to work

as for ahci over ide mode,  youll see a little improvement in benchmarks but nothing too solid in actually performance gains.  I still would rather use the ahci over anyhting else.

Lets windows handle the caching unless your going ssd,  there no ahci control panel to worry about either

4kb is now the default allocation size for ntfs so I would go ahead and leave that at default

never heard of any issues with stripe(allocation) size,  maybe only in raid.


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## dustyshiv (Jul 9, 2010)

AHCI does offer Native Command Queing and Hot Swap feature!! Correct me if Im wrong!!


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## RoutedScripter (Jul 10, 2010)

Yes , For the most part , im after NCQ ,  thanks guys , gonna install it now.


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