I just went through this whole ordeal last month. Tried quad core with 12 gig and a i7 920. I tested it with 10 boxing. The i7 is sooooo much better ad handling it. Hopefully you know how to set up core affinities, since that is how you get the best out of you processor. Go for the I7 920. And make sure it has capabilities to go to 24 gigs of ram(6 slots). The I7 was a bit more, but its CPU mark was at the top of the charts