Does evga gforce gt 720 2gb ddr3 or pny gforce gt 730 2gb ddr3 is support on Asus p5

Solution
That motherboard will likely NOT work with a PCIe 3.0 card, even the absolute garbage that is the gt720 and 730. See if the bios updates claim compatibility, if not assume they are not.
Why are you upgrading the GPU? Neither of those GPU's are what I would call gaming GPU's. They are so weak, they are really for PC's that don't have integrated graphics and just need a display but not intended for gaming.

PCIe is supposed to be fully backwards compatible so those cards should in theory work bit I have never tried a 3.0 card in a 1.0 slot
 


Communications IS backwards compatible, power is not. That's where you'll run into issues, especially with PCIe only cards like those two and even the 750