Please explain more? Are you asking whether it is worth the trouble to load a AHCI driver for your SATA drive, or should you just set the BIOS to IDE mode?
For me, I just built an XP media PC based on a new AMD E-350 motherboard with a conventional SATA hard drive, and I just put the drive into IDE mode.
I've been building computers for nearly 15 years and I don't remember seeing this abbreviation until recently but then there are so many "initials" these days that I may simply have missed it. Anyway there seems to be a lot of conversation lately so I associated it with W7. Recently I bought a SSD and research tells me that SSDs like ACHI so I tried setting my BIOS to ACHI and got a BSOD upon first boot. I set it back to IDE and all is well. Since I'm running XP that experience seemed to confirm that ACHI is only for W7 but I thought I'd better ask.
I GOOGLED "ACHI driver install on XP" and lifted this quote from a Toshiba website claiming to show how to do this:
"Many users would like to have Windows XP on their machine installed instead the preinstalled Windows Vista.
The problem is: when trying to install Windows XP on a newer machine with an "SATA AHCI controller", the harddisk would not be recognized.
The reason is: Windows XP has no SATA drivers included on the setup CD and the HDD would not be recognized from the installation wizard. "
My reading of this quote tells me that I already have such a driver installed because I have no problem with recognition of my HDDs when installing XP. Would you agree?