I was getting frustrated at low frame rates in several games, so I decided to finally take the plunge and overclock my processor (which I'd planned to do since I bought it 2 years ago). I managed to take it from 2.53Ghz to 2.99Ghz, and surprisingly that made a huge difference, especially in Red Faction Guerrilla. I went from struggling with the driving sequences to having them mostly smooth. Hopefully the overclock will prove to be as stable as it seems. My temperatures are still under 50C, which is more than fine for a Core 2 Duo E7200.
I didn't feel like running a lot of benchmarks before and after, so I just did some runs with Batman: Arkham Asylum. At the settings I played through the game with, the benchmark minimum framerates (which I consider the most important) went from ~20 to the mid-40s, which is a pretty giant leap. My CPU is definitely the limiting factor at 1280x720 and 2xAA.