% Processor Utilization is not equal to, or have anything to do with Processor Speed. There is a work load that the CPU must accommodate. Now, is it going to do it at 100% of its rated speed, or is it going to do it at 125% of its rated speed? Utilization is still the same, but at 125% of rated speed, how can you not get the same work done faster? Does this make sense?
As to not seeing improvements with a CPU overclocked, I can only assume that whatever was used as a benchmark in real life was either disk bound, or memory bound because memory was not tuned properly (or the modules were not matched properly to the processor) leaving the CPU waiting on the memory subsystem. Sorry guys. It is rocket science. You have to understand all the factors at play.
For a Sandy Bridge motherboard chipset, which memory timing is better? 7-7-7-17-1T or 9-9-9-24-1T? What speeds can these modules be run at? Rhetorical of course, but if you cannot answer these questions, you have no business trying to OC anything. Stay AWAY from your BIOS. Save your money. Run a stock Intel CPU cooler/fan, and don't worry about another thing. - OR - Go ahead and educate yourself and have some fun. And, btw, not everyone has fun with this shit, so no shame in just accepting what you got. And for everyone in the middle, a reputable builder will get this all done for you at a reasonable cost. A cost below what some high-brow gaming system company (Alienware(Dell)) would sell it for, but possibly more than the Big Box Store deal-of-the-day.