Enabling AHCI mode AFTER Windows Vista or Windows 7 Installation

A lot of users who buy SSD drives, install Windows 7 in IDE mode and then realize they need AHCI mode for faster SSD performance. However enabling AHCI in the BIOS after Windows installation will cause the OS to crash and not boot.

The common question is, is there a solution for this?

Well if your motherboard uses any of the Intel ICHR9/10 chipsets, the answer is, YES! There is a way to safely enable AHCI mode. Here’s how: (as always MAKE SURE YOUR SYSTEM IS BACKED UP BEFORE PROCEEDING!)

1. Start “Regedit” from the run menu
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 your system and enter BIOS (usually tap the “Delete” key while booting)

In your BIOS select “Integrated Peripherals” and OnChip PATA/SATA Devices. Now change SATA Mode from IDE to AHCI.

You can now boot into windows 7, the OS will recognize AHCI and install the devices. The system will require one more reboot after it has finished installing the devices and voilá .. enjoy improved SSD performance.

Please note: I cannot safely guarantee that this will work on chipsets other than Intel’s ICHR 9/10 chipsets, so do this at your own risk.