Cheers Andi, your summary was much appreciated 
As for something to stress the processor, f@h aside I've written some poor matlab code that takes a very long time to run. It's only single threaded, but that one core is going flat out for quite a long time. I seem to remember mathematica taking six hours on a problem at 4ghz, but I didn't check how multithreaded that was. Pretty strong indication that I should have stuck with my e8400 really.

As for something to stress the processor, f@h aside I've written some poor matlab code that takes a very long time to run. It's only single threaded, but that one core is going flat out for quite a long time. I seem to remember mathematica taking six hours on a problem at 4ghz, but I didn't check how multithreaded that was. Pretty strong indication that I should have stuck with my e8400 really.