Originally Posted by root
yes, it's true that the speed is limited. worse, after the installation there is no guarentee that you can change the setting back since that'd be a major hardware change and windows would either refuse to boot or at best require re-activation.
If I recall correctly the way to get around this issue is to slip stream SATA drivers into the windows XP install image then burn a new disc.
if you google slipstream XP you should find a guide on the microsoft website telling you how to do this,
I don't see any mention of XP in the OP, but for the record, it's possible to install Vista and 7 on a system with IDE enabled in the BIOS, and then change it over to AHCI once the correct drivers are installed for the motherboard. It's just a registry key, I do it all the time. Neowin Guide: How to change from IDE to AHCI without reinstalling Windows - Neowin.net
(I've never had to change the second part of the instruction where they mention PCIide, but it makes sense...)
The performance hit, by the way, is negligible for some tasks in Windows. NCQ and the other techs made possible by AHCI don't have much of an impact until you start really hitting the hard drive, things like multimedia streaming, video editing, etc.