A few years back, the answer would have been a fast dual core. But now, games are starting to correctly use more than 2 cores, and with next-gen games having at least 6 cores to work with, it will only get better.
So, the quad core is better.
Yeah I was wanting to buy the quad core one. The sides right now games do not need a cpu with a really high clock like the one with 3.90 GHz. A 3.40 GHz cpu is fine and will be for the next 3 years at leas. Thanks for the reply anyway!