Doesn't really matter these days. Even when playing the most demanding videogame the proc still waits periodically for input, either from the user (you
) or the rest of the system (video card, harddrive, etc).
AMD gives you more cycles for yer Pound, but Intel has the faster CPU. It's a matter of budget and personal preferences. If you're a gamer (and it sounds like you are) then invest in a better GPU then a CPU, as well as max-ing out the RAM and having an SSD as your main system drive (plus a large conventional one for storage). Have at least SATA-II connectors to attach the SSD to, SATA-III is not widely in use and difficult to find ATM. Alternatively, there are SSD solutions that mount a whole bunch of flash-chips on a PCIe card, giving even higher performance (but at a price, both in terms of pennies spend and storage available, although with the recommended separate storage drive this doesn't need to be too much of an issue)