Overclocking the Toxic X1900XTX
As we neared the end of our testing, we spent a little time overclocking the Sapphire Toxic Radeon X1900 XTX using the clock frequency slider available within ATI's Catalyst driver suite, under the Overdrive tab. To find the card's peak core and memory frequencies, we slowly raised their respective sliders until we began to see visual artifacts on-screen while running a game or benchmark, or the test system became unstable.
Due to the fact that the Sapphire Toxic Radeon X1900 XTX is scheduled to ship at higher clock speeds than a standard Radeon X1900 XTX, and we tested the card at its higher clocks, it was obviously faster than a "stock" card. We were hoping that the Toxic's liquid-cooling apparatus would allow for even higher frequencies though, and we weren't disappointed. When we let ATI's driver's detect the Toxic's optimal frequency, Overdrive reported peak core and memory clock speeds of 689MHz and 801MHz for the core and memory clocks, respectively. However, we took things a step further and were actually able to max out the sliders available on the overdrive tab for final overclocked speeds of 690MHz and 801MHz. We also tried overclocking the card using a third-party tool, but at 700MHz / 810MHz we could not complete a loop of 3DMark, so we backed things down to 690MHz / 801MHz for additional testing. With the card configured at these clocks, we re-ran a couple of tests and saw marginal performance increases in both, as you can see in the graphs above.
While we had the card overclocked, we also checked the GPU core temperature after running a handful of benchmarks and found that the core ran at about 60oC after an extended period of use and it peaked at about 88oC. That's not too much lower than we've seen with the stock Radeon cooler, but the Toxic's liquid-cooler does its job much quieter than the stock cooler.