From memory my cpu was either 5 gig or 5.2 and the 5970 was overclocked to match the clocks of my stock 5870.
Thanks for the update johny dolan.
In that case I've quite some distance to go to in order to improve my 3dmark11 score. The XFX 5870 clocks are 850MHz/4800MHz and the highest I've ever clocked the 5970 is 840MHz/4560MHz purely for benching.I'm currently gently-pushing the CPU/GPU in turn until I get BSOD or heat becomes too much. I'm updating my sig as I overclock on new build (new high score is P7,520 in my sig.) as I now have some room to push the 2600K a bit more. There's no way I'd get to 5.2GHz as that would mean going over the recommended vcore of 1.35 by quite a bit. I'd be quite worried going near 1.4vcore.

