Neither. The temp probe on the motherboard is VERY inaccurate. If you care about your cpu and are overclocking, pic up a compunurse. It's between 10-15 dollars but VERY VERY worth it! Have it touch the side of the core BARELY. i mean like the side, not affecting hte ability to cool the core. It will be as close to accurate as u can get.
-JokerF15