42.5% faster according to Cinebench R10. But that doesn't mean that a Q8200 isn't gaming capable if that's what you're asking for. The Core 2 Quad in that comparison is clocked at 2.33 Ghz. I'm sure that bumping up the clock a little would shrink the gap.
Q8200 should be capable of a good overclock if you have a good motherboard and the right ram. It has a low multiplier so you have to run the clock speed of the motherboard pretty high, and this runs the ram at a pretty fast speed. I'm running a Q9400 at 3.4GHz right now, I've run it at 3.8GHz in my testing and it ran fine.