Thrush, a dual core processor has 2 x 2.26hz cores both running at 2.26ghz. I have a quad core running a 2.4ghz on each core. I does not work out that dual or quad cpu are like the equivalent of a single 5.52ghz cpu etc...

As long as the software program you use is written for multi-core cpu's then they are almost unbeatable. I personally think the intel quad 6600 offers the best value for money(£150) I can encode a video, listen to music and browse the net at the same time. This is just not possible on a single core chip.