I checked the DAZ forums and as far as I can tell one dude there bought the I7 and is having major problems with Carrara 6. Take that for what its worth...
There's also a lot of discussion about whether or not running C7 on a 64bit OS has any advantages, or how much RAM Carrara is capable of utilizing. Of course nobody seems to know :)
It's a good thing I'm a few weeks away from ordering any parts...