hi folks, I noticed in the Title I put EHC1, of course it should be EHCI I am about to install my new ASUS P5K Pro mobo. I had some questions on settings in the BIO but I got most of the answers in the listing. This one had got me, BIOS EHCI Hand-Off In the manual it statesAllows support fo an OS without an EHCI Hand-Off. What is that. I have a drive caddy that I use to swap my OS drives, one for Vista and the other for XP Home. XP is fom my MSoft Train Simulator, it doesn't care much for Vista. Should I enable EHCI or disable. Thanks for any assistance.