Good choice, going for the 2600k. I recently read a review of the new sandy lineup, and I was wondering why the 2600k didn't overclock as well as the 2500k. I just did a bit of Newegg research, and I guess it's because the 2600k is a hyperthreader! You can probably hit some nice clocks on that thing if you disable hyperthreading for Superpi-ing.