520 3 pin not 4 , 212 is better . Those temps you're getting are VERY GOOD , if they are accurate , if you are not going to OC don't bother with a cooler unless the noise bothers you , then again the 212 might not be the quietest . Logiysis mc 3002gx is what I use on my lightly oc'ed x6 1100t and temps @100% cpu use are never over 53c , it was over 62 @100% @ stock clocks with stock cooler . the 3002 is dead silent and keeps things cool .
so disregarding the 3 and 4 pin difference which is better in performance