I figured I'd chime in here and add some 4 core vs 6 core info.

I just changed the PC that I am boxing on from an intel core 2 quad q9550 (2.8ghz) to a 6 core amd 1055t (2.8ghz).

Obviously the system boards are different but all other components are the same (Hard drives, video card) with the exception of RAM.

I am seeing less CPU use and less memory usage on my amd 6 core machine with 5 clients running (innerspace). I averaged between 5GB and 6GB of use with everything running on the Core 2 Quad CPU. Now with the AMD chip I am averaging 4GB of memory used.

Both systems had 8GB of RAM with the difference being my 6core AMD machine having 1333mhz speed RAM and the Core 2 Quad having 800mhz RAM.