Interesting benchmark here, showing what oc'ing does to game performance for the 3870 and 9800gtx. Its broken down into gpu, shader (9800gtx) and memory oc'ing to see what effect that has individually, together with the results of having both chip and memory oc'ed.
...but its in German. The graphs are easy enough to understand, 'speicher' means (video) ram and when they say 1xAA or 1xAF that just means no AA or AF. 4 game tests and of course 3Dmark06.