Hello. I will soon be upgrading my Mac Pro 5,1 from the stock Radeon HD 5770 to an NVIDIA Quadro P4000 running the web drivers for Mac OS. I have the 16x PCIe slot above the Radeon HD 5770 free and the Quadro P4000 is a single slot card with fairly low power consumption considering its capabilities. Is it possible to run the stock Radeon card and the NVIDIA card simultaneously so I can have a boot screen from the stock Radeon card and the additional power of the NVIDIA card? Thank you for your input!