Nvidia gtx 970 or 980 with web driver?

[5th Element]

Anyone have any experience using these in an older mac pro, 5,1? I have one installed and it seems to work well, however changing the mix type to anything but the default causes playback issues. Curious if it is just the graphics card.
Thanks!

[ping141]

I´ve tested a bit on a GTX 980 Ti on a hackintosh that has worked well, no issues that I can remember.

[THOMASL]

I tested GTX 970......works fine with 4HD output, but old GTX560 has better performance in playback....change back to 560..

Anybody tested 980ti? with 4k out