When I updated recently to 10.10.3 my Nvidia graphics card stop working (black screen) so I reinstalled the original card that came with my MacPro 3,1 to get it to boot properly. Then I downloaded the updated driver from the Nvidia site and the new card is working once again (without boot screen as always).
Here is the question: When testing to make sure the new card was working I left the old card just in case. As I mentioned, everything worked like a charm but I'm wondering if there are any advantages / disadvantages to just leaving the old card in the tower. I've heard about running dual GPUs but I believe this only works with a matching pair though. Thoughts?