While graphics drivers and third-party utilities allow you to overclock your graphics card’s GPU and memory, the pixel shader clock speed can only be increased through the card’s BIOS. These settings are permanent, independent of the graphics driver and the process is easily reversible. Games like Oblivion that make extensive use of shader effects benefit greatly from the increased pixel shader clock speed. Since the graphics drivers do not permit changing the pixel shader unit’s speed, setting the frequencies manually by adjusting the card’s BIOS is the quickest way to achieve your own optimized overclock.

For this article, Tom’s hardware used the MSI Geforce 8600 GTS Diamond Plus card to experiment on. The card sports a powerful fan and comes with a heatpipe cooling solution. Besides, MSI allows the card to be overclocked dynamically by up to 10% through the driver. These are ideal conditions for the GPU, memory and shader units to run stably at their new frequencies and the graphics chip to remain cool.

In order to reprogram an Nvidia card’s BIOS, you’ll need the tools Nibitor (3.5), Nvflash (5.5) and a boot medium such as a DOS-floppy or a USB stick. While the process as described here covers the Geforce 8600 GTS, the individual steps can also be applied to any other Nvidia graphics card just as easily.