750Ti Flickering on 2009 cMP

[Bollockser]

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.

 

[Flint Ironstag]

Hit up MVC, he may have seen this before. I haven't.

 

[IIcx]

I have the 4gb evga 750ti in my 3.1 unflashed, 10.11.6. It has been fairly trouble free so far, no issues across dvi, hdmi, or display port. There is a bit of wierdness/artifacting in Adobe Premiere cs4, but that may be due to the apps age, but elseware its been flawless. I doubt this would help, but have you tried different pci slots?

On mine currently have ver. 346.03.15f06 for the web driver. Cuda is 8.0.63