I've just bought U2515H and have it working with HD7850 video card. The problem: everything that is black on the screen flickers (from the lack of a better word) into dark grey. I noticed it in Windows background, but it happens in applications also. The colors (black/grey) change back and forth at a steady frequency of about 1/s, maybe a bit quicker. This only occurs with 0,0,0 RGB, doesn't happen with any other color. Also, this happens only with the Standard color preset.
I've tried both HDMI and DP and it occurs with both. I don't have this issue with the same video card but a different monitor. Curiously, this issue doesn't occur when I plug U2515H into my laptop with integrated video card. In diagnostic mode, when the screen is all black, there is no flickering.
Any help would be appreciated.
PS. I'm pretty sure that the other color is 1,0,0 RGB, it's impossible to tell them apart (tested in MS Paint), unlike, e.g. 0,1,0.
Because you do not have the issue when using Standard on the laptop and during the monitor diagnostic mode, the monitor is not at fault. The culprit is either the AMD HD7850 or its driver. You might have to test several revisions of the AMD driver. You should also test every available port on the AMD HD7850.