Hey everyone, I have a 2008 Octo mac pro. I recently got two new nvidia gt120's for it. I noticed that after about 15 minutes of use, or if I use a program that puts ANY load on my CPU, my mouse jumps around like its having a seizure. It makes the computer UN-usuable. It started after I updated to OSX 10.5.8, and It continued even after I installed Snow Leopard. I tried resetting the PRAM, Doing a repair disk permissions, changing the surface the mouse is on, using a wired mouse, a wireless mouse, changing mouse brands and NOTHING worked. Can someone please help me? Im about to ditch this computer. Its becoming a $4500 frustration generator. I use an MX Revolution desktop mouse (wireless) I tried a logitech G7 wired mouse, and it didnt help. I also tried a kensington wireless mouse and still had the same problem. The problem is most noticeable in iTunes. I also tried different USB ports.