We continue to make overclocking part of our testing suite with new cards and drivers. Enthusiasts push the limits on their hardware, and we feel we must test the overclocking abilities for you as well. Although NVIDIA did not add an overclocking tab in the driver control panel, it can be unlocked by using Coolbits - which is available on the Web - or by manually editing the registry. Again, we stress that overclocking voids your warranty and can shorten the lifespan of your hardware (you probably do it anyway, but we have to make the disclaimer.) For our tests we used the stock aluminum cooler that came on our reference cards.
We were able to get the single card's core up to 621 MHz and the memory up to 1.81 GHz (recall that stock is 550 MHz core and 1.7 GHz memory). The score we obtained using the default settings in 3DMark 2005 yielded a score of 9,538 but with the overclock we were able to boost the score to 10,939, an improvement of almost 15%.
The SLI scores were a little lower; we were not able to push the overclock as high as with the single card. We could get it to initialize at those speeds but the system would crash. The core went to 610 MHz and the memory to 1.78 GHz. This yielded a score of 13,316 in 3DMark 2005; compared to the initial score of 13,044, the overclock yielded a boost of only 2%. Obviously, it doesn't seem to make much sense to overclock the SLI setup, while single card users can do a little and get a lot back. The combined overclock percentage for memory and core was about 9.7% but this led to a gain of 15% in the score.