Same as Windows XP, many users are trying their ways to improve Windows 7 running speed. And some the most common methods are to optimize system services, disable some useless system services and optimize explorer menu. Besides, there are some “uncommon folk prescriptions”, which is said to let Windows 7 speed up twice.
  If you want to try the method shared here to let your Windows 7 run faster, first of all, you must ensure that your motherboard supports AHCI.
 Tip: what is AHCI?
 AHCI, the full name is Serial ATA Advanced Host Controller Interface, under the direction of Intel, it is a interface standard developed by several companies. And in AHCI, Intel import NCQ(NativeCommandQueue) function and hot pull-and-plug technology. After hard disk supporting NCQ technology receives read/write command, it would resort the visiting address according to the command, reducing access time and making data transmission more effective.
  If your motherboard supports AHCI, then please before installing Windows 7, enter BIOS setup, in the option “Advanced”, set the default IDE in SATAcontrollerMode to AHCI.

Notice: enable AHCI to speed up Windows 7 system twice
 Please attention, different motherboards have different BIOS. Please find the relevant items when set up.