Underclocking The Radeon X850 XT PE
Anytime a new flagship video card that isn't based on an entirely new core is released, many users will cry out and proclaim that the new card is nothing more than an overclocked version of the old one. In the case of the X850 XT Platinum Edition, that would mean it's simply an overclocked X800 XT. If that is in fact the case, the X850 XT and X800 XT should perform identically when clocked at the same core and memory speeds...
To find out just how similar the X800 XT and X850 are, we underclocked the X850 XT using Powerstrip to 520MHz (core) and 1.12GHz (memory), the same core and memory clock speeds of an X800 XT Platinum Edition, and re-ran a few benchmarks. In both Doom 3 and Half-Life 2, the underclocked X850 XT Platinum Edition was slightly faster than the similarly clocked X800 XT Platinum Edition. But the performance difference deltas were quite small. For all intents and purposes they performed at the same level. The fact of the matter is that the R480 core used on the X850 is essentially a tweaked R420 core that has been slightly reworked to attain higher clock speeds.