Hello people. I'm having a very frustrating problem and would appreciate if anyone has any idea on how to remedy. I have a GTX 780 6GB from macvidcards installed in my Mac Pro 5.1. I am running 10.9.4 with web driver 334.01.02f02 with CUDA 6.0.51. Everything was working just fine for a couple weeks. I didn't update drivers or install anything new and suddenly both CUDA and OpenCL are broken - bringing my work to a grinding halt. Cuda-Z and Ocean Wave both tell they won't work. I've tried upgrading and downgrading the CUDA driver, but no luck. Preview crashes and QuickLook fails on tiff images - not sure it this is related but it started at the same time. On macvidcards' recommendation, I installed OpenGL Extensions Viewer and Unigine Valley. I get a score of 1589 on Unigine Valley with the Extreme HD preset. OpenGL Extensions Viewer opens and gives me lots of info but I don't know how to use or interpret the data. I did run the tests and it passes 3.1 through 4.1 but fails 4.2 and 4.3. Again, not sure what this means. In system profiler everything appears normal: Chipset Model: NVIDIA GeForce GTX 780 Type: GPU Bus: PCIe Slot: Slot-1 PCIe Lane Width: x16 VRAM (Total): 6144 MB Vendor: NVIDIA (0x10de) Device ID: 0x1007 Revision ID: 0x00a1 ROM Revision: MacVidCards I'm also unable to boot into Win 7 via bootcamp. I just get a black screen, not even a blinking cursor. I get nothing when holding F8 or Fn+F8, so no option for safe mode. I also get nothing but black when I try to boot from the Win 7 DVD. Not sure if this is related to my video problems. Please let me know if you have any ideas about how to solve or diagnose my problem. Much appreciated.