ATI Radeon HD 4830 Launched Today - Reviews Inside

This new model is, like the 4850 and 4870, based on RV770 silicon, but in its tamest form yet. Yes, folks, the great product segmentation game continues with yet another chip having perfectly good—or possibly totally flawed—bits and pieces deactivated to maintain a neat separation between models. On the 4830, two of the RV770's 10 SIMD units have been disabled, reducing shader power (and likely performance) somewhat. Since those SIMD units are tied to texture management units, the GPU's TMU count has dropped proportionately. The end result: the Radeon HD 4830 has a total of 128 shader execution units—or 640 stream processors, in AMD parlance—and can filter up to 32 textures per clock.

That's it for the neutering, though. The 4830 keeps all four of the RV770's render back-ends and associated memory controllers intact, leaving it with an aggregate 256-bit memory interface. The card's GPU core runs at 575MHz, and it comes with 512MB of GDDR3 memory clocked at 900MHz (or 1800MT/s, for those of you keeping score at home.)