I just purchased a Sapphire HD4830 and have checked using the current production 0.2.8 gpu-z and the test build from the test build forum, and both are showing 800 shaders: The default clocks are those of a 4830. Do I have an mismarked and underclocked 4850? Or is gpu-z getting erroneous information from the BIOS? I'm also interested in how gpu-z gets the hardware information. I first heard about gpu-z from the stories about the initial batch of HIS cards with the non-production BIOS under-reporting the shaders, so I assumed that the info comes straight from the BIOS.