The two cards overclocked nearly identically. The XFX card was able to reach 709 MHz on the core, but was not stable at that clockspeed when running tests (even though nTune’s driver said it passed the test. The XFX 8600GT XXX Edition was able to overclock to 670MHz successfully and stably, nearly the same as NVIDIA’s reference 8600GTS card. The EVGA Superclocked was also able to overclock to 671MHz using nTune, but the highest stable clock speed where I could run games was 650MHz. The two cards are brothers to the 8600GTS, meaning that they are close to that level of clock. Here’s a screenshot of the EVGA 8600GT running at 671/866 core/memory and a shot of the 3Dmark06 score as I was testing overclocking. Another shot, this time of the XFX card overclocked and it’s 3Dmark06 score. As you can see, even though the two cards are clocked differently on overclock, the 3Dmark06 score is only 100 points higher.