After our standard round of benchmarking, we fired up Rivatuner 2.09 for an overclocking test on the XFX GeForce GTX 280 1GB XXX. The XFX card is already an overclocked card, so naturally we wouldn't expect much more headroom for overclocking.

We made a wild guess and went to 740MHz on the core and taking the shader along to past 1600MHz with the 'link clocks' option enabled. Unfortunately, it was a little too much and the card gave us additional eye candy of black triangles and boxes before blanking out halfway through Futuremark's 3DMark Vantage.

It seemed like we were quite close to the sweet spot and we went 735MHz on the core, 1575MHz on the shader, and 1325MHz on the memory. We just decided to set some nice numbers, as the actual clocks are 734/1566/1325 because of the crystal used to generate the card's frequency. The memory is rated at 0.8ns, but we managed to squeeze a good 75MHz (150MHz DDR) more out of it.

Overall, that's a 60MHz-odd overclock on the core, 200MHz-odd on the shader and 75MHz more on the memory over the factory default... And that also makes it an overclock of approximately 135MHz, 275MHz and 225MHz on the core, shader and memory respectively over a NVIDIA reference clocked card.

The following are the results we got in Futuremark 3DMark Vantage with 735/1575/1325 in Extreme and Performance presets:

Well, if we had been able to up one more notch on the core, shader and memory clocks, we would be seeing a 6,000-odd and 13,000-odd score for Extreme and Performance presets.