How to change the hard disk from ATA to AHCI under Windows 7 system

Before solving the problem, first understand the relevant knowledge:
1. What is the AHCI function?
The full name of the Advanced Host Controller Interface, the Chinese translation: Advanced Host Controller Interface, which is a technology led by Intel. Can take advantage of the potential acceleration of SATA hard drives, which can increase the read and write speed of hard disk by about 30%.
2. What is SATA hard disk?
Serial ATA hard disk is evolved by PATA:Parellel ATA; SATA is currently mainstream, with fine cable and fast transmission speed, while PATA cable is wide and slow. Old computer hard drives use this architecture, will be replaced by generations, commonly known as IDE hard disk, so new computer to choose SATA hard disk, and need to be SATA2 specifications.
3. What are the requirements for AHCI?
1 hard disk drive must have the function of NCQ (Native Command Queuing), which is usually a SATA2 hard drive. Currently sold on the market is a SATA hard drive. It should all be this specification.
2 computer motherboard South Bridge chip, to have the ability to support AHCI, so the old computer is not available.
3 computer BIOS to open AHCI function, not open can not enjoy
first step, modify the system registry.
Start Menu - Run, type regedit Enter, enter the registry editor, find the following location: HKEY_LOCAL_MACHINE/SYSTEM/CurrentControlSet/services/msahci
Change the value of Start under this item to 0
Step, restart the system, modify BISO
Reboot the computer, enter the BIOS (for example, my system is F12 when booting), then select into the BIOS.
Find the hard disk settings in the BIOS settings, modify the ATA For AHCI, then save and exit the BIOS.
This way, after rebooting, Windows 7 will automatically install the AHCI driver.