I know you didn't ask for advice on your build but i recommend against the 680i. I have had so many problems with mine. Since you haven't ordered yet, try to research another chipset. Maybe P35 or X38, I don't know what your budget or needs are.
Im regretting this way overpowered overkill that I have... But it will never be obsoleted and it has got a lifetime warranty so thats alright. And it cost less than the HX 620. PCP&C FTW!!!
there is nothing wrong w/ the 680i A1 and 780i's .... this 680i i have has went through harsh overclocks through mgcook... and now me... and has yet to show me any negative feedback