You can certainly go up to at least 3.0ghz with stock, no need for voltage boosts either.Intel stock sux, but it can manage because heat increases exponentially in relation to speed, so you can go a decent speed with the stock, but for marginally higher overclocks, you will need an aftermarket.Ive heard of people overclocking it to 4.0 Ghz with stock heatsink, but i would get a better one anyway