Even at 4.5ghz the 4100 is slower than the i3. It depends on the games you want to play really, the 4100 overclocked would be better for massive multiplayer games, but you'll need a good aftermarket cooler and you'll use twice the power and create twice the heat and not really have any upgrade path.
If you go the i3 router, it's green, and has an Ivy Bridge upgrade path.