With up to 2 GFX cards, the 6700k will have the best performance, followed closely by the 6500k. The 5960x would be the choice with 3 or more GFX cards ... however, with the future of SLI w/ 3 or 4 cards now in question with the 10xx series, would suggest a "wait and see" approach if considering more thsn 2 cards.