An overclock is limited by one of two things - thermally or voltage, you have to stop when you hit the peak on one or the other. Almost all Ivy Bridge CPUs hit a thermal limit on the stock cooler before they hit a voltage limit. However a decent after market air cooler will allow you to push up into the 1.35 V range, which is arguably as high as you ought to go unless you are suicide benching. High end air will do the job.
You do get less power consumption with a cooler CPU, and in theory at least you need a lower voltage to achieve the same clock speed. In practice it doesn't make a great deal of difference as the prebuilt water loops are only slightly better than the high end air setups. I suspect the cooler you have will likely be good enough to achieve a decent overclock but you might be thermally limited before voltage. But really that is more about Ivy Bridge and its stupid thermal paste problems and not really the fault of your cooler not coping. Delidding and applying your own paste would solve that problem as well as the heat issues.
i7 3930k @4.4, 2xMSI GTX 680, 16 4x4 GB Corsair 2133 RAM, Crucial m4 500GB, Dell U2410 24" and 2x Samsung 2443 24", Xonar D2X. All custom watercooled by 2x MCR 320 and 1 MCR 480
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