I had a 3,1 since my purchase in 2008 and it's been a rock solid machine. Since then I've only upgraded my MacBook Pro's and I finally got my friends MP5,1 (which I plan to upgrade the CPU's later)...right now its 2.4 x 2, 28GB RAM and I put my SSD from my 3,1 and it's a pretty rad machine. It gets 14447 Geekbench and I know if I get the the X series six core CPUs it goes up to the 28k range rivaling the new mac pro. Oh also put in a GTX780 in this baby *Mac Hacked* and this machine is incredible now. Just wanted to let you guys know that there is still helluva lot life left in these 4+ year old machines.