For Nvidia/AMD Graphics Cards: RivaTuner
For graphics card lovers, there’s an effective overclocking solution: RivaTuner. This very complete application isn’t limited to Nvidia cards; it can also be used to overclock AMD cards. (For those of you who remember that Nvidia’s cards used the name Riva many years back, we talk about this in our article on Nvidia graphics cards.)
The application lets you overclock without any real limitation on frequency—you can go much farther than AMD or Nvidia would want you to go using the overclocking interface in their own drivers, in any case—and RivaTuner can also de-synchronize certain frequencies. An interesting point about RivaTuner is that it can change the frequency of the shaders independently of the GPU, whereas other programs can only act on the GPU (with the shader frequency set as a reference to it).
RivaTuner is available right here. It’s the utility we used in the second episode of Tom’s Talkback to help adjust the fan speed of 4800-series Radeons before the Catalyst 8.10 package was available.