Hmmm, I have a rather recent mobo/BIOS and a SSD housing my OS, so I'm going to have to look into this. 

Benefits of being a tinkerer. One of the first things I do is browse through every page of the BIOS.

Yeah - I agree.  I always read up before I build and then do the appropriate tweaks.  Pretty lame if you bought a custom pc and they didn't have someone sort through that.  I understand if you bought from dell or some such rot, but you'd think they'd tweak that if you bought a high end customized rig.  Anyway, better late than never, I suppose. 

Seconded!

Yes!!!!!!!!   Also, you will notice that I post from Wincustomize, so I would not have seen your post over at Sins, or the fix you speak of... or that it worked for some guy.

What I read elsewhere, however, is that Windows has to be reformatted because it cannot install the AHCI drivers prior to the BIOS change and subsequent reboot.. that Windows cannot reboot without said drivers after the change.  However, the article also said there is a workaround.  I have been in contact with yrag with respect to this... though I may still have to rewrite Windows.  Despite the best advice of yrag, my machine BSOD's at boot in the AHCI mode, just as the Win flag is about to emerge.

Luckily, I did did this other research, otherwise I would have been stuck with an inoperable machine and no remedy.  You see, when the BIOS edit is made, booting back into the BIOS to revert to default settings is not that simple.  As I discovered, it's not just a matter of pressing the delete key and waiting for it to load as before.  No, it just sits on a page listing the installed drives, with no way out... other than a hard reset.  To boot into the BIOS the delete key must be pressed continuously from the moment the reset button is pressed, otherwise the opportunity is missed.

Anyway, I have now been to the Sins post linked to above, and I will try the advised fix.  Thank you.  Hopefully it's a 'one fix fits all' and I can avoid having to reformat.

Thoumsin: enough already............

I used your reported link to fix, installed the Microsoft Fixit update, enabled AHCI 2.0 and no errors, booted fine.  Thanks!

Best regards,
Steven.

Sorry, that does not make any sense. IDE is an a harddrive-interface obsoletede by SATA, AHCI is a USB2-protocol. So you can perhaps speed-up USB harddrives by using the correct USB-protocol, but it would not influence the internal harddrives. In all the cases the BIOS-settings only affect boot-up speed, once the operating system is loaded it overrides almost all BIOS-settings anyway.

Okay, it's done.... AHCI using only yrag's method, no patches or files from MS.  The only difference to before, and getting BSOD's, is that I disabled the Vista drive and removed it from the MBR in msconfig.

Then all I had to do was go into Run> regedit> HKEY_LOCAL_MACHINE\System\CurrentControlSet\Services\Msahci and change the start value in the right panel from 1 to zero: then I booted into BIOS> Peripherals> SATA Values> change from IDE to SATA... then rebooted to Windows, and voila.  Win 7 loaded the necessary drivers, prompted a reboot and here I am... in AHCI mode.

I think next up I'm going to replace my current WD SATA'2's with a couple of SATA3's.... may as well take advantage of the higher speeds now I have the mobo technology to support them.

*EDIT*

The above registry key is for an AMD based machine and will not be present in an Intel based machine.  The registry key for an Intel machine is as follows...

HKEY_LOCAL_MACHINE\System\CurrentControlSet\Services\IastorV.... then right click "Start" and change the value to 0> reboot to BIOS to change IDE to AHCI> reboot to Windows.  If in Vista or Win 7 the OS will load the necessary drivers and prompt another reboot.

Once performed you're all set to go... in AHCI.

USB has OHCI, EHCI, UHCI, and now xHCI, as Jafo mentioned that has nothing to do with AHCI.

http://en.wikipedia.org/wiki/UHCI

The touted performance increases I read about actually came with my mobo information and specs, rather than a HDD manufacturer....

Yet another onboard feature of GIGABYTE AMD 900 series motherboards are integrated the latest AMD SB950 chip for high-speed SATA Revision 3.0 compatibility, delivering 6 ports native superfast 6Gbps link speeds for twice the data transfer rates of SATA Revision 2.0 (3 Gbps) and RAID 0, 1, 5, 10 support. When used in RAID 0 (Stripe) mode, GIGABYTE AMD 900 series motherboards offer even faster data transfer rates of up to 4x the speed of current SATA interfaces."

So yeah, to take advantage of the higher speeds supported by my mobo, SATAII devices just don't cut the mustard.  However, I will take your thoughts into account and give it some more research before splashing out the bucks on them.

I page through as well. But AHCI is listed as a RAID type thing in bios and since I wasn't running a RAID I didn't think anything of keeping it in IDE mode until I recently learned just how important it is to switch to AHCI.