Hi djeans,
I have no solutions for your issue.
Just came here to let you know I faced the exact same issue with my hackintosh (x79-up4 / i7 4930K / nvidia gtx ) too.
Mavericks was rock solid. This issue started showing after I upgraded to El Capitan, and later in Sierra too. I searched for a solution for months without any success. I couldn't use El Capitan or Sierra well over 6 months after I first updated. Luckily I had Mavericks in another SSD. It became quite a hobby for me for months to search the web for a solution. But I never found it.
Btw, Now I am using Sierra without any of those issues. I have absolutely no Idea what solved the problem.
Only thing I remember changing hardware wise is my monitors. Previously I was using a 40 inch tv with HDMI and a computer monitor with DVI. Later I replaced them with a pair of HP monitors, both with HDMI to DVI converters. I am a bit reluctant to accept that solved my issues, but I have no other clues. Your console screenshot is very familiar to me.LOL.
Anyway, I am still looking for a logical answer. Sorry for the long reply, but I couldn't help since i know exactly what you are going through.
Wish you good luck.