Well, for one thing, less volts usually equates to lower operating temperature and also gives you a lower starting point to get a possibly better OC. I had a San Diego 3700 that required 1.55v to reach 2.75 GHz. I've had 3 146 Opty's that hit 2.8 GHz on stock voltage (1.4v). I had plenty of room for increasing voltage on the Opty. Heat will be a bigger issue, once you start hitting around 2.8-2.9 GHz, expect load temperatures to approach 50C in 72F ambient air with air cooling. A good water setup or better will give you even more room....I'd never run over 1.55v on any AMD 90nm cpu, but that's just me, alot of people do with success....