both should be pretty similar as they have virtually the same specs (and at 1080p the difference in vram won't affect perfromance) but a 940M isn't going to do to well with a 1080p screen. What sort of games do you intend to play as you may want to look for something with a lower resolution screen as it will result in a better fps than a 1080p screen. If your only intending to play older pc games then both will be fine