Hey all - I have a weird issue getting 3 monitors to work on my tower. I have 2 Dell P2715Q 4k monitors that I run as my main monitors, running at 1440p HiDPI each. Both are plugged in using DP to DP cables and I have very little issue with them other than occasionaly one of them doesn't wake from sleep. My problem is when I decided to plugged in my old Dell U2410 as a third monitor, so I could run the video window in ProTools, and get extra realestate for my mixing windows (I do mixing for TV and Web series, from home). I originally plugged it in via HDMI>HDMI to my GTX980(Non-Flashed). It booted right up and I had a great mixing session moving the video window to this third monitor. I put the tower to sleep that night and upon trying to wake the computer, the tower's light went on, but none of the monitors turned on. I then did a hard reset and the 2x 27" 4k monitors turned back on just fine upon bootup, but the U2410 did not. I turned it off and even unplugged/plugged in the power cord. The 4k monitors blink like they detect that another display is turned on, but then the U24's screen says no connection detected. It's just strange that it worked beautifully that one time, but then doesn't any time after. It detects a signal as the monitors all flash, but then the U24's screen says no signal detected. Thinking maybe it's an issue with HDMI, I ordered another DP>DP cable (the same one I use for my 4k monitors), but that had the same issue. It worked the first time I plugged it in, but then as soon as the computer was shut down, it always detects the third display with a flash, but then the U24 displays no signal again. I'm stumped why it would work the first time on each new cable, but then never work again. I've tried different combos of Unplugging/Plugging back in the power cord to the U24 and the HDMI/DP cables on the monitors end and the GTX980s end. Any Ideas? Thanks! MacPro specs: 2010 - 5,1 - (2x)x5690 - 32gb OWC ram - GTX 980 SC ACX 2.0 - 500gb EVO for boot - (2x) 840pro 256gb on a Sonnet SSD raid card, sabrent 4 port usb 3.0 card.