Id agree with Robcrezz, but it also depends on a few other variables. Mainly resolution. If your gaming at 1080p, then yes the 8400 will be a about 10% faster, game dependant. If you plan on getting a higher res monitor 1440p or above, then the difference in FPS for both CPU's is less. In that case I'd go for the 2600 which has twice as much host processing, which can be great if your thinking of streaming further down the line. Then the 2600 would be the much better buy.