Installed Window7 in IDE mode and changed back to achi

. The system was reinstalled some time ago. The previous system was the new driver when the ghost win7, the hard disk mode was changed to IDE, this reloaded forgot to change to achi mode, forcibly modify bios After achi mode, win7 keeps restarting and can't enter the system. But the system has been installed, and it is too much trouble to reload it once, so I found a solution on the Internet, mainly to modify the registry, as follows.
1) In IDE mode, enter win7, find the registry
HKEY_LOCAL_MACHINESYSTEMCurrentControlSetservicesmsahci, double-click the Start option on the right, modify its value: 0
2) Restart the system, enter bios, modify the hard disk mode to achi, save After rebooting.
3) After entering win7 normally, the system will automatically install the achi driver, OK, successful.
The reason why I want to change to achi mode, I believe I don't need to say more, in theory, the speed is faster than the traditional IDE mode. But this time I did the test before and after the modification. The tool used was HD Tune Pro 4.6. The read speed of the hard disk before and after the modification did not change much, basically the same. But since it's a sata hard drive, changing to achi will theoretically yield better performance.