In the next few years, games that run on two threads will obviously run better on a Dual Core PC because the two cores will be able to take half of the game each. So if you had a 4800+, it would be like running half the game on 1 regular 4000+ and the other half on the other regular 4000+. However, there is a pricing issue. For roughly the same price, you can get a Dual Core 2.0GHz CPU or a 2.4GHz Single Core CPU. IMO, single core CPUs will always be faster than Dual Core CPUs. If what we're thinking right now is right, then yea, a Dual Core CPU will be better than a single core in games. But I'm starting to question our way of thinking
Looking at FEAR right now, Dual Core CPUs don't make a crap of a difference (and FEAR is supposed to support Dual Cores). In My Honost Opinion, I think that the increased speed of a 2.4GHz 4000+ will make up for the 2 cores of a 2.0GHz X2 3800+. Seems illogical, but seems true.