Hi, Just wanna know if these two GPUs are supported on this ancient PC. If yes, please suggest the minimum capacity of the PSU that I should go for. 750 Ti seemed to be a bit underpowered based on the games I intend to play on it. I've changed the default SFF casing to a micro-tower one. Specs: i3-2120 3.3 ghz 4GB RAM 320W PSU Thanks very much.