Even with the power of the AMD Athlon X2 and Intel Extreme Edition processors, we still find ourselves hitting a CPU limitation in a lot of our benchmarks. That is, the graphics cards have more performance to give but the processor is letting the team down.
By overclocking the processor we can see what kind of a performance increase we get. When something isn't CPU limited the performance increase isn't all that major but when we do have a CPU bottleneck, every MHz extra we can get can show us an excellent jump in performance.
The AMD Athlon X2 3800+ Socket 939 was increased from 2GHz to 2.6GHz with a slight increase in the front side bus utilizing air cooling.
The X1900GT clearly sees a more significant performance increase at both resolutions with the overclocked processor when compared to the X1800GTO.
The low resolution test saw the HIS X1800GTO increase in leaps and bounds but no effect seen at the higher resolution, the X1900GT managed to see a negative affect with the overclock with frame drops of roughly 10%.
Low resolution results see a minor increase for the lower end card but when it comes to the higher resolution (where it's all graphics cards doing the hard work) the difference isn't seen and in turn we can even see negative results.