Before I got more RAM I used to run games on 4GB RAM, there was no real issue however there were problems when other applications were open, such as Chrome or Fraps. 8GB would be the perfect amount because you could also run other applications alongside your games. I was running games such as Borderlands 2, Bioshock infinite, Far cry 3, Skyrim etc......... but when Memory usage spiked for general reasons the games would lag which really does take away from the experience. but the majority of the time it was fine. Get 8GB though to be 100% safe