I tried to get the UP2715K working on my cMP with a flashed 7970 with no luck so I'm looking at other options now. The flashed 980 from MVP is a little out of my price range so I'm considering the Nvidia NVS 510. I don't game or edit video or anything. I'm just a web designer/developer. It looks like it can run 2 of these displays at 5K in a PC, so it's possible (http://superuser.com/a/874569). I just worry about support in the Mac Pro. I've seen a few people using them in Macs while googling (http://forums.macrumors.com/threads/nvidia-nvs-510-efi.1830398/). I realise I'll have no boot screen of course. I have a 7970 or a 5870 I can use for that. It's not listed under supported products on the Nvidia web driver page but then neither is the 980 or 970 so is it possible that driver will also work for the NVS 510 and allow 5K as it does on a PC?