I am shooting 4k on my Sony AX33. Footage gets saved as MP4 100mbps. Kind of hard to edit in FCPX on my early 2009 Mac Pro Quad Core 2.93 MHz 16g, even using pro res. I was thinking of upgrading to high spec iMac Late 2015, but I decided to wait until next year when the more powerful and quieter AMD gpus should be available. In the meantime, I though I might upgrade MacPro with: * Sapphire HD 7950 Mac Edition; and * Mercury Accelsior E2 PCI Express SSD for boot drive/project files (I only work on 1 project at a time, so this is plenty large). Will I see better performance in FCPX? My cpu never get's higher than 50% right now, which leaves me to believe there are other bottlenecks.