Seems there was a bit of a mix-up with ATI's lastest release, the HD 4830.

A number of review samples went out with 560 shader processors, when instead, there should be 640. Missing 80 shaders will give you game performance a big kick to the guts. Roughly, having 80 less shaders translates into a 10% performance cut.

Our HD4830 reviewed had 560 shaders -- we had to re-test the 640 shader ATI HD 4830, and have since updated our review.

After some investigation, it seems like a portion of the HD 4830 cards distrubruted by board partner HIS are missing the shaders. If you've purchased a HIS HD 4830, it is highly recommend that you run the program GPU-Z and double check the amount of shaders you have.

If you are missing shaders, the problem is fixable -- it is only a matter of running a program that will re-flash your card's BIOS. ATI has told us that the updated BIOS will be located on the HIS website very soon.