"If you're planning to spend a couple of minutes on overclocking, you should go for the raw cpu megahertz overclocking ... which is fairly obvious. Everything else gives a nice boost, but that's it; no real extreme increases in performance. Note that it's important how you interpret the graphs: this is a performance scaling investigation, not an overclocking scaling investigation. Please understand that the given increases are expressed in comparison to a very low base frequency, not at stock speeds. For instance, the performance scaling of the HT Link frequency may seem very impressive in the 3D benchmark, but if you look more closely, you'll notice that 1GHz is almost enough to maximize performance."
(~ AMD Phenom In-Depth Performance Scaling Analysis)