The thing is, overclocking comes in two flavours now:
* Too small to notice
* Too big to be stable
I can recall a time when a mere 17MHz overclock made a real and tangible difference in daily performance (K6-233, ran at 3.0x83, was an incredible beast)... but when I ramped up a E7200 (2.66GHz stock) to 4.0, all I saw was a lot more heat, a lot more noise, and a lot less stability.