The 185 will probably not have much headroom compared to the lower models of it's series. On air, I wouldn't expect more than 3Ghz, and more likely closer to 2.8. The only reason to get such a chip is for the high multiplier if you need it. A 170 or 175 would still be a better deal as a 10 or 11 multiplier will still get you to 3Ghz easily on most boards and it is very unlikely you will be able to push it higher without phase-change cooling.