I am receiving a lot of emails from users who installed Windows 7 in IDE mode and then realize they need AHCI mode for faster HDD performance. Once you enable that in the BIOS during Windows 7 boot up, the OS will crash.
The common question is, is there a solve for this ?
To answer that question (and I do this safely with all Intel ICHR9/10 chipsets) there is a way to safely enable AHCI mode. Here we go:
1. Startup "Regedit
2. Open HKEY_LOCAL_MACHINE / SYSTEM / CurrentControlset / Services
3. Open msahci
4. In the right field left click on "start" and go to Modify
5. In the value Data field enter "0" and click "ok"
6. exit "Regedit"
7. Reboot PC and enter BIOS
In your BIOS change SATA Mode to AHCI from IDE.
You now boot into windows 7, the OS will recognize AHCI and install the devices. Now the system needs one more reboot and voilla .. enjoy the improved HDD performance.