Sure the Core 2 Extreme is fast, but it's also expensive. How much performance can you wring out of the more budget oriented E6300 and E6400? What we didn't know previously however was how far we could overclock retail E6300/E6400 CPUs, and furthermore we had no idea what a highly overclocked 2MB Core 2 Duo CPU would perform like. Armed with two B1 stepping Core 2 Duo CPUs, one E6300 and one E6400, we went to task on overclocking them. Our goal wasn't to reach the absolute highest overclocks using high end cooling, but rather the maximum stable overclocks easily attainable with a stock Intel heatsink/fan. Undoubtedly we could have reached higher frequencies with more elaborate cooling, but we were more interested in the bare minimum of what was attainable - and we weren't disappointed.

AnandTech