I wanted to start this thread as a guide for me and others on confirmed and un-problematic 4K systems on the cMP as there is no definitive guide as to what monitors work with what OS X or GPU or cables etc etc. So here are 2 set ups I have tried: ______________________________________________________________ cMP 2009 4.1>5.1 3.46 12 core cMP with 48GB 1333 RAM OS X 10.10.2 GTX 770 2gb (non flashed) Display port 1.2 Samsung U28D590 monitor Natively supports upto 3200 x 1800 @ 60Hz with no problems. BruceX bench mark here exports in 118 seconds ______________________________________________________________ cMP 2009 4.1>5.1 3.46 12 core cMP with 48GB 1333 RAM OS X 10.10.2 Gigabyte R9 280X 3gb efi flashed Display port 1.1 with mini DP to DP HDMI 1.4 Samsung U28D590 monitor Natively supports upto 2560 x 1440 @ 60Hz with DP which is a bit fuzzy or full 4K with HDMI 1.4 which is clear and crisp but @ 30Hz. BruceX benchmark exports in 55 seconds. ______________________________________________________________ If you have a stable 4K set up with the cMP please post your details as above so we can build a bit of a list of products that work well with OS X, cMP, cables, Monitors and bias on the side of FCPX. Just as important is the users experience and price of set up.