Yes, my card is native PC one. But it works in Maverix and Yosemite. But it appears to be 7xxx. And I think it doesn't give hardware acceleration, as no speed up after NV GeForce 285 in FCPX of Compressor.
I'm trying to find information about flashing my card as it is not reference (reference has only one DVI port, however I don't need the second one).
(something like this, but mine has different DVI ports - dvi-i and dvi-D, I need only DVI-D port)

Also, I have 2560 x 1440 on my DVI-D port, but only lower on HDMI port... I can't understand why.
P.S. I have native Mac Pro 3.1.