Hi, I'm sorry if this has already come up or has been solved, but I'm someone stumped. I recently acquired a Mac Pro 2008, dual quad core for nearly nothing. I've in the process of "hot rodding" it for video editing, photo editing, etc. I have OSX 10.9.4 on a Crucial SSD + 2 TB WD black drive set up as a fusion drive, am keeping the onboard 8 GB RAM for now and have added a Inateck USB 3 card. I've been messing with the above EVGA GTX 660 card in slot 1 with limited success. The card works fine for normal desktop, but I've been fighting with CUDA and OpenCL support. I believe I have Cuda working correctly - I had to jump back to the 6.0.51 to get CUDA-Z to find it; 6.5.14 doesn't seem to work. OpenCL is odd. I've tried the built in OSX and nVidia 334.01.02f02 drivers, but openCL seems slow. LuxMark V2.1 results in a score of 524 - TomsHardware shows a LuxMark 2.0 bench of 3787 for the GTX 660. Also, when I do a system report, PCI cards shows as "There was an error while gathering PCI card information." The card seems to be working ok; FCPX Trial seems snappy, but DaVinci Resolve Lite 11 is almost unusable and Steam games crash. Any idea where to look? I'm at a loss at this point. Thanks EDIT: The CompuBench CL test suit looks WORSE using the GTX 660 than the system CPU but bench higher... The card never seems to get warm. I have it drawing power from the MoBo as it should be.