More likely in the 3.5TH range, with overclocking. Unless you live in the arctic, the Bonus Neps like to overheat/shutdown due to KnC not including thermal pads. You'll want to install good heatsinks, or upgrade the fans, or both, depending on how much you want to spend. (listed in order of cheapest to pricey) Once you get them running, they tend to stay running fairly well. They can lock up every once in a while though.