You already have a preety good system, but if you want to, upgrade the GPU, you wont see any real increse from an i5 to i7, i5 is already a future proof cpu that will last forever, even then the 670 is a top card, the only upgrade worthwhyle would be to a ,690,780 or titan.Keeping in mind that the 780 costs 600+ that is what i would upgrade to.