Windows 7: AHCI : Enable in Windows 7 / Vista

Hello atlcraig.



I'm glad you were able to get it sorted, thanks for the update.

Just to put in here for nForce users, nForce boards do not support AHCI (with the exception of nForce boards that include onboard graphic cards), and also don't send the TRIM command for SSDs. It can do NCQ through its controller though. The JMicron SATA ports do support AHCI, but you'd get worse performance running a HDD through these, than on the normal SATA ports.

You can uninstall the Nvidia controller though in Device Manager and install Microsoft's IDE Controller, which can send TRIM commands for SSDs.

Head to Device Manager (Open Start menu, type Device Manager), and click "IDE ATA/ATAPI Controllers", and you will see 3 Nvidia Serial ATA Controllers. Right click one of them and click "Properties" and go to the "Driver" tab. Click "Update Driver". Click "Browse my Computer", and then "Let me pick". You will see the option to choose "Standard Dual Channel PCI IDE Controller". Click this and click "Next" and let it install.

Do the same for the other two Nvidia Controllers in Device Manager and restart your system. After the controllers have installed, you will be asked to reboot again.

SSDs will now have a slight performance boost with the TRIM command, and also regular HDDs also have a slight increase as well.


Feel free to add any of this to the first post, if you want Ted. Some nForce users might benefit from it.

Thanks EL, as you know the info has been added to the first post after the tutorial.

I just made this post so others will know of it.

I've used this process before on my PC, switching to AHCI gave me a pretty decent performance boost... I find it's more helpful for maintaining the speed of a computer though. As data on a drive becomes more fragmented, it doesn't affect your PC speed quite as much as the standard SATA mode.

I have a question though, I want to configure two spare 80GB SATA drives I have in RAID0 to see how they perform... Should I use this same process beforehand to get Windows to reinstall the drivers? I would think so, simply based on the principle behind this is to get Windows to redo drivers... But I'm not sure due to the key being named 'msahci'. Anybody care to clear that up for me?

Edit: Just to explain why I'm asking this, I'm going to Ghost my C:\ and restore the image onto my RAIDed 80GBs, that way I don't need to reinstall everything from scratch... If this process is an option, I'll end up making the registry change before Ghosting my C:\ partition, that way when Windows starts up with my drives in RAID mode it'll attempt to reinstall drivers on that boot.

Hello ZaLiTH.



In my BIOS I have the option for AHCI or RAID, not both, I'm sure it'll be the same way for yours; you would need to change it to RAID before OS installation.

Did I misunderstand your question?

When I changed HDs recently I switched to ahci because I wasnt raiding them. I feel it is slower.

Yeah, think you did a little bit there... I know it's AHCI or RAID, which is why I said:
The only reason I'm asking here, is regarding the drive controller drivers that my Windows installation currently has (for the AHCI configuration). When I first installed, it was straight SATA mode, then I used this tutorial to switch to AHCI mode, now I'm asking if the same process can be used to switch from AHCI to RAID.

This tutorial would be used to get an already installed copy of Windows to reinstall the drive controller drivers, right? So, by my logic; I would (1) change the registry setting as mentioned, (2) make a Ghost image of my C:\ with Windows and put it on an external HDD, (3) shut down and install my two 80GB drives in RAID0, then (4) restore the Ghost image onto a partition created on my RAID0 array.

Well, let's put it this way, I'm not going to delete the partition with Windows on my 400GB until I know it's working properly with a RAID setup, so I'll try it this weekend regardless and then let you all know how it went on Monday.

You mean AHCI was slower? Well, if you were comparing it to RAID0 or RAID5 (with a decent controller), then yeah, it would be slower than RAID..

Hello again.


I thought so, as I have no experience with RAID I'm no help for an answer but I'm curious to know the outcome so please post back to tell how it sorts out.

Definitely, I will.. I'll be changing my setup over the weekend, so that gives me time to figure out the finer details and do some "before and after" benchmarks. I'll post the results of that in the performance sub-forum on Monday.

mine shows 3, should i change it to 0? strange thing is that my laptop has the AHCI option in the bios, but windows or the registry shows "3"