I made a driver disk for use during Windows install, before I installed my new mobo.
The manual is a bit rubbish around this bit to be honest, but as long as you've got access to another computer, or you do it before you pull your old system apart, the easiest way to make the disk is to do what I did.
I just inserted the Gigabyte CD into my drive, navigated to the Bootdrv folder, double clicked Menu.exe which opens up a DOS type window and then chose the driver I wanted, in this case Option 5 which is the Promise 20779 SATA Driver which will enable you to run a SATAII HD in AHCI mode enabling NCHQ etc.
It installs the driver to a blank floppy disk you'd have prepared earlier!
You then use that during Windows install, when you remembered to press F6 earlier when Windows asked you if you needed to install any 3rd Party drivers. (Sorry if any of this teaches you to suck eggs by the way, I'm only trying to be helpful!)
Without this driver, my HD seemed to be a lot noisier and slower when loading apps etc after my first install without using the driver disk.