It's now been two months since Half Life 2's release and much to everyone's surprise, the game was far from a GPU hog. The more powerful your graphics card, the better everything looked and the smoother everything ran, but even people with GeForce4 MXs are able to enjoy Valve's long awaited masterpiece.

Immediately upon its release we looked closely at the impacts of GPUs on Half Life 2 performance in Parts I and II of our Half Life 2 coverage. Part I focused on the performance of High End DirectX 9 class GPUs, while Part II focused on mid-range GPUs as well as the previous generation of DirectX 8 class GPUs.

The one area we had not covered up to this point was the impact of CPUs on Half Life 2 performance. In a 3D game, the CPU is responsible mainly for the physics of the environment as well as the artificial intelligence of the NPC elements of the game. There is also a good deal of graphics driver overhead that taxes the CPU, and thus with more complicated games we get higher dependencies on fast CPUs.

Half Life 2 was an intriguing case in itself simply because the game boasted the most sophisticated physics engines that had been seen in a game to date. Elements of the game such as the gravity gun would prove to be extremely taxing on your CPU. In fact, we found that even the fastest $500+ video cards can still be CPU bound in Half Life 2 at normally GPU limited resolutions.

Although much delayed, today we are able to bring you the third and final part of our Half Life 2 coverage focusing entirely on CPU performance as it relates to graphics performance in Half Life 2. After all, a $500 graphics card is worthless if it is bound by a slow CPU.

All of the tests in this article use the same test beds and testing methodology as our first two Half Life 2 articles. You can download all of the demos used in this article here.

We apologize for the delay in the publication of this article, but as often the case, we get busy and things such as this article get postponed and postponed. Rather than shelve it, we decided to publish it - better late than never. Now on to the benchmarks...