Well if you wanna get like that, not a lot of games are CPU intensive. Only a handful - depends what he wants to play.
Well, very few are as GPU intensive as BF3 SP. It changes a bit, even with BF3 MP. BF3 MP will take all of the CPU horsepower (cores and
raw speed) that you can give it.
Beyond that, a 6200 at stock will still be a bottleneck for a 680 in most situations.