You might want to start by uninstalling the utility. You will have smoother experience if you overclock using the BIOS instead. All you need to do is change the OC mode to manual, and adjust the multiplier to 4.2. Use HWMONITOR to keep an eye on your temps and voltages. Be sure to disable turbo, cool n quiet, CE1, C6, and APM. You should be a able to hit between 4.2-4.5 Ghz with stock voltage. Just change the multiplier, boot, stress test for 5 minutes and if everything is ok, try another multiplier bump for an extra 100Mhz and so on until you become unstable.http://www.cpuid.com/softwares/hwmonitor.html
It's been my experience that 4.5Ghz is about as high as youre going to get with a Hyper 212 Evo in "Turbo." I had to keep my rig "laying down" for the Hyper 212 to do its job correctly. Setting it vertically as it should go made the temps skyrocket by 10 degrees+.