Dual 765M will perform a bit better than a single 770M, however, do you really want an Alienware? Or do you just want a good, powerful gaming laptop? And what's your budget? You might want to take a look at Asus G750, they have models with 765M, 770M, and soon, a model with the 780M. Their laptop looks sleek, and has a far better cooling system than Alienware. Another option to go with is SAGER, they are a true gamer's favorite. They don't care about looks, all they care about is performance, they have a 2500$ laptop that packs dual 780M, that's 110FPS in battlefield 3 multiplayer!