As long as the profiler that is native to the OS you are running is accurate, what does it matter??? What system is this about Hemingray? Have you tried the gauge pro utility to see what it lists?? Don't be too surprised if it varies by a one to three MHz. The utility is getting long in the tooth, and cannot handle the newer processors (gets confused by them 🙄 )
As for overclocking a Mac, only do it if you don't care about the system. If you are a whiz with a soldering iron, then attempt it, if not, leave it alone. I am fairly certain that xlr8yourmac has instructions on their web site... Look them up and see what you can get. If you have AppleCare on your system, I wouldn't do it. When the computer is well out of warranty, then you can, but until then you would void the warranty by overclocking (unless you are REAL good at undoing the stuff you do).
I read an article yesterday in a peecee mag about overclocking of systems. Essentially the guy writing the article states that a few years ago where processor speeds were not where they are now, and people needed to overclock to play a game (at a reasonable speed) overclocking was worth it. But, today, that is no longer the case, nor is it needed. I left the mag at home today, but I can put up that section later if anyone wishes... Or PM me and I will send the entire article (less then one page) to you...