Hey! I have the same mobo/cpu combo that you do, and was able to clock it up to 4.8Ghz using this guide
Keep in mind that your CPU cooler will have a big impact on how high you can overclock. I was able to reach 4.8Ghz stable with the NZXT Kraken X60, and 4.3Ghz with a Coolermaster Hyper TX3.
My voltage is currently set to 1.425, which is the lowest setting I can have before it will become unstable. Try not to have your voltage exceed 1.5v, as this will almost certainly damage your CPU/mobo, especially if you are using your cpu at full load for long periods of time.
If you want, I can give you my full specs of the overclock when I get home, as I am at work right now. Let us know how it goes! GL!