I still wouldn't even buy a 2 x 6-core at this point. We are talking August 2010 released machines here, and it's May 2012. We've advanced two major chip releases since then, added Thunderbolt technology (released) and SATA III/6G (released) and none of that is implemented on the 2010 models they are STILL selling. It's old tech, I would have said buy one in late 2010 or early 2011, and go with the 6-core if you get one...but now, I would say DON'T buy a Mac Pro right now at all...The current 27" i7 iMac even packs newer technology than the 4-core Mac Pro. What the iMac is lacking is Internal expansion (drive bays) and PCIe card slots/Graphics card slot -- which the Mac Pro is the only machine Apple offers with this expandability. The need for an expandable Mac is the only real driving reason you should want a Mac Pro at this point, not to have a "power" machine with the latest tech.