I know there is another post similar to this one, but this one wont be so broad. Im hoping to OC my XP2100(1.73ghz) to 2Ghz or more. I was thinking about one of these coolers: Alpha PAL8035 Thermalright AX-7 Thermalright SK 7/SLK800 (which is the latest? Im a bit confused) Swiftech MCX462-U w/ Thermaltake 80mm Smart Fan II Which would you say would be the one to get? BTW, what are shims for/what do they do? Thanks!