3DMark Vantage (Performance Preset)
We can see that the GPU scores reaches a plateau around 2.2 Ghz.
On the other hand, CPU score increases linearly as we increases the CPU frequency.
Crysis Warhead (Gamer Preset)
For Crysis Warhead, we can spot a similar trend, FPS reaching a plateau after some frequency.
This freqeuncy varies,
2.5 Ghz for 1680 x 1050 No AA
2.1 Ghz for 1680 x 1050 4x AA
2.1 Ghz for 1920 x 1200 No AA
1.7 Ghz for 1920 x 1200 4x AA
For 2560 x 1600 resolutions, its a different trend altogether as shown.
Far Cry 2 (Ultra High Preset)
Far Cry 2 seems to behave in a slightly different manner. The frequency at which the FPS starts to hit a constant seems to be the same for both AA disabled and AA enabled settings. For Crysis Warhead, it is the AA enabled settings which will hit the constant much earlier than AA disabled settings.
Another point is that at a resolution of 2560 x 1600, the FPS for Far Cry 2 responds to increasing CPU frequency whereas Crysis Warhead does not respond at all.
Nevertheless, all three benchmarks demonstrated how CPU frequency can affect the FPS/performance of a game.
However, further testing showed that the FPS of a game might not be affected by the CPU frequency at all. We shall carry out more tests and update soon. Do stay tuned.