Hello and welcome to the forums
I'm not sure about GTX 460 but HD 5770 should work fine http://store.apple.com/us/questions/product/MC742ZM/A
"I have a MP 2007 2,1 Will this card work in my system? It's the 3Ghz dual quad core (8 total cores) MP."
"Yes, its working great on my workstation, MP 2007 2,1. it feels much faster than my old ATI Radeon 1900."