I would say that that quad you have is a better architecture, not to mention has twice the cores, so for handbrake and other multithreaded apps, I would expect the AMD to lose. Usually by a decent margin.
However, I have a core 2 duo E6550 in my desktop at home, and it has a lower clock speed than your proc. In most cases yours is faster and mine is not terribly slow. I've encoded movies before and it gets the job done in less time than I'm at school.
Here is a website with a quick rundown on the proc you have and its performance. It seems to be quite the overclocker.
http://www.neoseeker.com/Articles/Hardw ... 250/4.html