Shortly after I published my Radeon HD 4830 review and the Blu-Ray playback performance article I was notified by AMD that every reference card they sent out to reviewers came with an incorrect BIOS. The BIOS that shipped on the Radeon HD 4830 had one too many of the SIMDS disabled and the result of this is that the Radeon HD 4830 had just 560 stream processors enabled instead of the 640 stream processors that it should have been running. After the launch AMD released the following statement along with a new BIOS.
AMD has identified that a very limited number of ATI Radeon™ HD 4830 boards have shipped with an incorrect BIOS which may impact performance. This is in no way hardware related, and an updated BIOS fully resolves the performance limitation. AMD has provided its board partners with the updated BIOS. Please contact your board manufacturer for instructions on updating the card BIOS.”
The original BIOS installed on our reference card was VER011.012.000.002.030222 and GPU-Z reported that the card had 560 unified shaders.
I used ATIWinflash to flash the vBIOS with the new vBIOS that enabled the right number of stream processors, which should improve performance.
With the new video card BIOS installed and the system restarted I fired up GPU-Z and it showed that the installed vBIOS on the reference card was now VER011.015.000.003.030656 and GPU-Z now reported that the card had 640 unified shaders. By enabling these extra 80 shaders means that the graphics card now has ~14% more shaders, which means that performance should improve.