The RV770LE graphics processor (GPU) is a "lite" version of the RV770 GPU that went into making the Radeon HD 4850. Out of the 800 stream processors (SP) the RV770 has, AMD carved out the new GPU by disabling two blocks of 80 SPs each, resulting in a 640 SP-laden Radeon HD 4830. Earlier, GPU makers would simply make a BIOS edit that disabled blocks of shader units. Both NVIDIA and AMD these days, resort to physically modifying the GPU, making irreversible changes to the amount of SPs available for the GPU to use. On the sample TechPowerUp got from AMD, there were three such blocks (perhaps accidentally) disabled, crippling the SP count further down to 560.More details about the issue can be read over here.
This did reflect in the card's performance against the one PowerColor sent based on the same GPU. The card from PowerColor outperformed the reference card due to its "proper" stream processor count. We urge reviewers and enthusiasts to verify the stream processor counts of their Radeon HD 4830 samples or products using the aforementioned build of GPU-Z.
Some Radeon HD 4830 cards have only 560 shaders
Posted on Thursday, October 23 2008 @ 19:48 CEST by Thomas De Maesschalck