If you're talking about a 4400+, each physical core operates at 2.2GHz and has 1MB L2 Cache so it's basically like having two 3700+ San Diego cores...one is processing your gameplay and the other one could be doing something like burning a CD or something, if you look at it that way, it's quite a powerful processor
And of course one games become multithreaded both cores can be used to split the load meaning your processor is going to be powerful in a wide variety of enviroments for quite some time