Re: 2 different graphics cards in 1 system
Generally speaking, yes, it is!
But the GTX 770 is designed for 4k resolutions so you might as well try (testing) to run it alone first!
To run both cards you might need a better PSU and there must be a reachable vacant PCI-E slot!
At any case, the answer to the original post is yes, but the CPU could be a bottleneck if two demanding games are running! Still, the argument that you can try first, providing the PSU can cover up for it and the mobo has a vacant PCI-E slot, is still there!
Remember that you might need to alter the settings in the nVidia CP and that the game supports detecting more than one monitor!