The models you picked can't handle games like Crysis in high settings which need a A class graphic card.
Accourding to your budget, Dell Alienware M17X is the best choice.http://www.laptopforgames.com
He wants a 15-16'', the Alienware is 17''. It is also more expensive at its base configuration then the 15'' Sager is. And they have the same graphics card.