I overclocked my E6600 (2.4GHz) to 3.1GHz with very little difficulty and hardly noticeable increase in temps. That's a 30% increase pretty much for free! I'll take that any day. You just have to bump it gradually and stress (Orthos is great) it a lot after increments. I'm sure I could go much further but this room gets hot enough in the summer and I'm certainly happy with what I've got. You buy all this hardware that's designed for OC'ing, it's a shame not to at least go a little ways with it. overclock.net btw, is a really great web site. It's worth hanging around there. You pick up all sorts of info you won't get anywhere else.