what the hell is this?

what is APIC MODE - MPS version ctrl for o.s. ? the options are 1.1 and 1.4. What is this?, What do overclockers use: 1.1 or 1.4 ? Is there any advantage in choosing any of these 2 options?

I forget what APIC does besides the fact that if it is enabled/disabled and you change it you will need to reinstall Windows to get your comp to boot again. Most overclockers pay it no mind and ignore it for the most part.

For windows 2000 and XP you use 1.4. 1.1 used by NT3.51 and below. HERE is a link with a explanation what APIC does.