All it does is underclock your proc when you aren't using it. It is a good idea to disable it when you are OC'ing.
If you're OCing, you don't have a choice. If you leave Cool N Quiet enabled, when your processor is "woken up" after being idle, it will ignore your BIOS settings and go back to stock speeds. If you're not overclocking at all, there's no reason to turn it off.
Nothing will happen, if you are overclocking, disable it. Its a waste IMO.
Also, I found that removing the AMD driver fixed some problems with multipliers on another board. I never use the AMD driver..
A forum community dedicated to overclocking enthusiasts and testing the limits of computing. Come join the discussion about computing, builds, collections, displays, models, styles, scales, specifications, reviews, accessories, classifieds, and more!