Ok, I will give this a shot. The rig with the tri-core has 2 280x's on it and my 6-core has the other 4. My i7 rig has the gtx 590. I'll try pausing the cpu's and see what happens for a few hours. Thanks everyone
You should be good then, and could probably fold using a core or two on your 6-core and i7 rigs. Basically you want to keep 1 core(thread?) free for each GPU, +1 extra free core. So keep all cores freed up on the tri-core, 5 cores free on the 6-core (or maybe just 5 threads free if it's intel with hyperthreading....not sure how it works for intel), and 3 cores(threads?) free on the i7 since the 590 counts as 2 GPUs.