I totally forgot about this thread and have some updates.

I now have to Nvidia cards running in the Mac Pro both being powered by an external PSU. No boot screen but the machine works fine and rendering speed has nearly doubled. I had to ditch the stock AMD card but that thing was garbage anyways ...

I have a 12 Core 2010 Mac Pro which I recently upgraded for Octane. I kept the stock AMD card to run the display and added a EVGA GTX 980 TI 6b solely for Octane. The new card required more power so I've hooked it up to an external 850 watt EVGA battery that sits on top of my Mac Pro. The system ...