Heat

What heatsink are you using? Stock? Get rid of it, it's hard as hell to mount correctly! An Arctic Cooler Freezer 7 Pro is ~$30, insignificant compared to the price of everything else!

AC7's don't really start to do their best work till you OC. I'd recommend a Tuniq Tower, Thermaltake Typhoon VX or if you're really feeling adventurous, a Vigor Gaming Monsoon II TEC.

But who'd buy a 680i and a C2Q Extreme not to overclock?  

Good point, now imagine what the ones I recommended will do. :wink:

Oh, yeah... The Monsoon TEC cooler, that's serious business!

For air cooling get either Tuniq Tower 120 or Thermalright Ultra 120 w/ push pull fan. That should keep the temps down. Also you can mod the side panel of the case and place a single 120mm fan blowing air in towards the cpu cooler which helps really well in keeping the cpu temps on the low. Like they said if you got the money get that Monsoon TEC cooler for sub ambient temps on idle.