I got a flashed EVGA 750Ti from MacVidCards, the 2GB version. I have a 2009 MacPro 2x2.26 Quad, flashed 4,1>5,1 I put El Capitan 10.11.6 with the correct web driver for the OS build, and newest Cuda driver. Not working properly. In system profiler the card IS recognized, but the Cuda control panel says No GPU Found. During startup I do get the boot screen, but the progress bar looks weird, and when the Finder opens there is bad flickering, and the system is terribly sluggish at drawing anything - the machine is not usable. I used the HDMI port but have not checked the Displayport, although I can't imagine this is the problem. I have searched the internet and found this flickering is a common problem with this card, Mac and Windows alike. Can anyone recommend a combination of MacOS version and Cuda driver version that will allow this card to run properly on my setup? The next phase will be me trying different MacOS versions and driver versions but it won't be long till I give up and sell the card. I hate to give up on this card because I love that it is a low energy consumption GPU. Any help greatly appreciated, until then I'm dead in the water and out for the money.