If you have a Serial ATA (SATA) hard drive in your computer, you can increase the read/write performance of the drive considerably by enabling the Advanced Host Controller Interface (ACHI) in both your computer's Basic Input/Output System (BIOS) and in Windows 7.
Not only is ACHI faster than the older IDE interface, it also supports advanced hard drive functions such as Native Command Queuing and Hot Plug, which the older interface cannot. By default, however, Windows does not enable the option. Therefore, in order to enjoy the benefits of ACHI, you will need to make some changes to the Windows registry.
Close all Windows applications and programs, then click the "Start" globe. Type "regedit" in the Search box, and then press the "Enter" key. If the "User Account Control" window appears, click the "Continue" button.
Click the "HKEY_LOCAL_MACHINE" link in the left side of the window, then browse to the "System/CurrentControlSet/Services/Msachi" value.
Locate the "Start" value in the right window pane, then right-click the entry. Click "Modify" on the pop-up menu.
Type "0" in the "Value Data" box, then click the "OK" button. Click "File/Exit" on the Registry Editor menu bar to close the application. Shutdown and restart the computer.
Wait until the computer restarts and you see the first boot screen, then begin pressing the "Delete" key or other key used to enter the system BIOS (Refer to your computer or motherboard user's manual for the specific key). Wait for the BIOS system menu to appear.
Navigate to the "Advanced" or "Advanced Settings" option, then press the "Enter" key. Scroll down to the "SATA Interface," "HDD Controller," "ACHI Settings" or other similar entry, then press the "Enter" key.
Change the value for the "ACHI Settings" or other similar entry to "Enabled." Press the "F10" key or other key used to save BIOS settings and exit the utility. The computer will restart. Allow the computer to boot into Windows normally. Windows now uses the ACHI interface protocol with SATA hard drives instead of the older IDE interface settings.
Things You'll Need
Motherboard with a BIOS that supports the ACHI interface
Computer or motherboard user’s manual
- TechMetica.com: SATA AHCI Mode Bios Setting - What Does it do?
- I Think Different: How to Enable AHCI in Windows 7 RC After Installation
- BeHardware.com: Test 6 HDD SATA 3 Gbits /s 250 GB
- Microsoft Support: Error Message "STOP 0x0000007B INACCESSABLE_BOOT_DEVICE"
- Windows 7 News and Tips: How to Enable AHCI in Windows 7