Overclocking
OverclockingWe've made explicit mention of the fact that PowerColor uses R480-based cores for its Radeon X800 GT GameFX 256MB card. R480 is the codename given to ATI's X850-series of cards, which number just three. The X850 XT PE, still the fastest ATI card to date, raises the core speed to 540MHz and memory to 1180MHz. The X850 XT runs at 520MHz core and 1080MHz memory and the X850 Pro chugs along at the same core frequency but does so with only 12 rendering pipelines. Chances are, then, that 520MHz should be on the cards (bad pun intended, folks). The bigger question is whether one can soft-mod it to either 12 or 16 pipes, turning it into a real X850-class card. For the moment, the answer is no, but you never know. It will be interesting to see how many users, if any, can activate any dormant, fully-working pipes. As it is, you're buying into a VPU that didn't make the grade. Anything extra is a bonus.
Testing frequency overclocking with DOOM 3 set to high-quality mode, we were able to push our sample's clocks up from the default 472.5/980 to an impressive, stable 540/1035. Our SAPPHIRE sample, based on the R423 core, managed to overclock to 515/1060 in similar ambient conditions.
DOOM 3 and Far Cry were re-run at 1280x1024 4x AA/8x AF, which, we reckon, represents the sweetspot for this midrange card.
Performance is, of course, dependant upon the game used. DOOM 3 has always run well on NVIDIA's hardware and it takes an overclocked X800 GT 256MB card to match a GeForce 6600 GT's default performance.
Far Cry, though, runs better on ATI's hardware. Raising the clock frequencies makes the benchmark play that little bit smoother.
