I believe that 3.1ghz i5 is a 1155 socket, also that PSU will run either card in single and dual just fine. If the CPU is the ivy bridge (can find a 3.1ghz besides ivy) then the Z77 boards will be the best upgrade. I'm currently running a 2500k on a Z77 with a 760OC and run BF4, Titanfall, SimCity, on high or ultra with 60FPS and have dual 24" screens.
Edit: forgot the 2400 was also 3.1ghz, still same socket though so Z77 still best go shoot for.