What kind of games?
Most will play at low-mid at native resolution.
Some new games like those running on Cryengine (crysis series) will make your GPU cry.
It's still a great machine, but if you want to game I highly recommend the 680mx for future proofing especially, the 660m won't be able to play some games on high even now, but it's your decision and depends on what you want to play