An E6400 isn't that powerfull, I mean it is a great chip, but if you look at cpu benchmarks with that use games as benchmarks, you will see that an x6800 gets significantly more frames in some configurations. Because often times your cpu is actually bottlenecking your gpu. I chose to overclock for several reason, one of which is that overclocking my fsb to 400, allows me to uwse my DDR II 800 in 1:1 which eliminated that ram load slow down entirely in source games. Coincidentally overclocking the fsb increased the clock a lot. I could have dropped the multiplier, but since it actually is damaging nothing to run it faster, why not?