Right now the studio is very outdated as the other poster said. Final Cut Pro doesn't even use more than one core. It's really pathetic. Try rendering or exporting in Final Cut, it's awful and uses less than 25% of my machine, which is a Quad Core i7.
Compressor does use all cores, but you MUST create a cluster as it will not do this on its own.
As for the RAM, 4 gigs is enough right now, especially if you are using mostly FCP.