My new UW monitor periodically freezes up like this and I have no idea why:

Other times, it will simply go totally black and the computer is still running. Does anyone have any ideas?
Here's some info.
I'm using a newly built computer. Here's the parts list: https://pcpartpicker.com/user/teacherjtaylor/saved/jyjFdC
Temperatures are ~30C at idle and 70c under full load.
I tried switching from a DP cable to HDMI, still getting the same thing.
Also tried changing graphics settings, including refresh rates. Does the same thing at 60, 85, and 100hz.
Tried it out on different titles. Witcher 3, Skyrim, and WoW at max and above-average settings. Getting the same.
I haven't run a memtest yet, which I probably should have done, but I'm not sure if that could be the issue. Computer is recognizing 16GB ram.
Anyone have any ideas? Please.