Mine is the e8400 and it has 2 cores (+2 hyperthreading). The q6600 has 4 (but no hyperthreading, I think). BTW I was thinking to upgrade to it back then. Off course it also depends on the GPU and RAM too. Did some research and found someone reporting with a similar setup I had (minus the CPU, as mine was e8400):
I'm trying to run as many (good) japanese PS2 games as I can on a computer that has an Intel Core 2 Quad CPU Q6600 @ 2,40GHz, 8GBs RAM, and an AMD Radeon HD 5700 series, and to my surprise, I'm very limited by the number of titles that run more or less decently, when this PC hardly has a problem running most Gamecube games (with Dolphin), or Dreamcast (with Flycast) games I feed it. Heck, for what very few original XBox titles I more or less managed to run (with Cxbx Reloaded), they run better! Castlevania Curse of Darkness for example.
- https://forums.pcsx2.net/Thread-LIST-The-Most-CPU-Intensive-Games?page=12
Now this bugs me even more, because I should have tried Dolphin and Flycast too. Would be fun to bring it out again and see what it still can do. But I'm not that bored enough to do that right now.