Here's what I have: Mac Pro 4,1 - 2x 2.93 Quad core Xeons, 48GB RAM, ATI 7970HD 3GB, 512GB SSD RAID 0 on a Sonnet Tempo Pro, 2x ViewSonic VP2770-LED screens. I'm at a crossroads of where I either have to: get an Apple PCIe SSD blade (for faster Xcode performance - big projects with lots of small files) get 2 4k screens for retina quality display (I'd prob. go with these: http://www.amazon.com/ViewSonic-VP2...&qid=1447511713&sr=8-1&keywords=view+sonic+4k) probably upgrade to 2 3.33Ghz 6 core Xeons. I'm kind of getting the feeling that I'm starting to waste my money putting it into this old box, though it still performs most tasks relatively well the tasks I need it for are starting to lag (Xcode). Having been spoiled by retina displays and faster performance with other devices I've been debating getting the 5k iMac - but I'll have to put a different display next to it for the real estate I need. The idea of having two non-uniform displays freaks me out a little. I'd max out the iMac. The other option is upgrade the Mac Pro and hold out for a new one though I feel as if it would be money not well spent. I'm thinking maybe the iMac for now, then sell it when a newer MP comes out and just hope ViewSonic still makes the display so I can have two matching ones. What would you do?