Ok this was originally a long post to write and i accidentally clicked BACK when i was going to publish.
basically i got 2 pcs, a laptop and a desktop, and i overclocked them.
Both had DDR2 667MHZ, C2D cpus and stock gpus.
I overclocked and got lower fps in games, longer boot times and increased heat.
Cpu-z also detected my desktop memory was at 233Mhz ddr and 466Mhz DDR2. So that means overclocking reduces performance. I could see my pc stuttering on Plants Vs Zombies when overclocked from 2.4GHz to 3.7GHz. 2.4GHz ran smooth 3.7Ghz was like grinding sand paper along sharp rocks.
The post that was original had more results but im not going to spend another 1 hr of my day writing it out again and getting a sore wrist.