Hi all, Today I decided to upgrade to Sierra on my 4,1 MP, so I flashed the firmware to 5,1, and freshly installed Sierra. Everything has gone well until I went to install the latest web driver (3184.108.40.206f03) with the latest CUDA driver (8.0.51) and swap out the GT 120 with my GTX 970 that I have been using on El Capitan. Anytime I try to boot using the 970, I get immediately put into a boot loop, and the MP eventually shuts itself off. I even tried adding "nvda_drv=1" to my boot-args, but the boot loop still persists. I've tried disabling csrutil and then installing the web drivers, but no luck. I've tried uninstalling and reinstalling web drivers, but no luck. I can boot just fine, with or without, the "nvda_drv=1" when using the GT120 card. Pretty much no matter what boot-args I set when using the GT120, it boots just fine. The minute I pop in the 970, the boot loop happens. One thing that is odd, is that if I try to boot with only one of my monitors (the one I have using HDMI), it boots just fine. However, if I plug my other monitor (VGA with a DVI adapter) in, it immediately goes into a boot loop. At this point, I'm completely stumped. I've had boot loops before, but they eventually loaded, they never shut down the computer all together. Does anyone have any ideas?