Yeah sorry I should have made myself clear, I wasn't considering an APU nor was I comparing a GPU with the APU I was merely curious but thank you for you help. One more question though, what is this 7870 LE I've been hearing about what separates it from a normal 7870?
Take a 7950 GPU, cut it back slightly, add on the memory configuration of a 7870, and you've got a 7870 LE. It performs out of the box around the same as a non-boost 7950, so it's an extremely good buy at £155.