The card runs here without any problems under Win7, with a Core I3, 8 GB ram. 2x 24" screens are controlled. 1x 28" should also be able to be operated smoothly, assuming corresponding processor performance and RAM. However, measure whether the card fits into your case (the dimensions can be found in the specifications), the KalmX is relatively large. Greetings Ceb
I installed it in my Mac Pro 3.1 and it worked wonderfully! But it's true, you have to work with the Nvidia Webdriver!
I also recommend keeping a second card, preferably the original Mac Pro one.
As soon as Mac Os X or the web driver are updated, the graphics card is sometimes not recognised, so you have to access it blindly (remotely) or start via an old card and install the previous driver.
With a Mac Os X update, the web driver is often uninstalled, which means you have to blindly reinstall the web driver again!
Otherwise the thing runs really well.