Install Window7 in IDE mode, change back to achi method

        The system was reinstalled some time ago. The previous system was the win7 of ghost when the new machine was purchased. The hard disk mode was changed to IDE. This time, the reloading was forgotten to change to achi mode. After forcibly modifying bios to achi mode, win7 kept restarting. 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_MACHINE\\SYSTEM\\CurrentControlSet\\services\\msahci, double-click the Start option on the right, modify its value to: 0 2) Restart the system, enter bios, modify the hard disk mode to achi, save Restart. 3) After entering win7 normally, the system will automatically install the achi driver, OK, and succeeded. 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.