I did some performance testing on build speed (VS2008 though).
I tried using RAM Drive. Almost no difference from RAID 1+0.
Quad core doesn't seem to help much as CPU is never at 100% (well, one of them is at 100% I guess). CPU frequency seems to help though. Not sure about memory speed.
So, to speed it up, consolidate some projects (since having same amount of .cs files builds slower if they are in separate projects) or create sub-solutions - solutions that only hold dependancies for your current work project. So, say you have Web app and admin app and some sort of WPF UI client, create 3 solutions, one with web app, one with admin and one for client.
