Hi, I have an opportunity to buy 2 Gtx 770's for $300 each. They are brand new and unused. My current setup has 2 Gtx 670's. I believe the resale value of 2 Gtx 670 is about $500 (correct me if I am wrong but I have replaced the original cooler with Antec Kuhler 620). Is it worth it to spend an extra $100 for may be 20% performance increase? I game at 2560x1440 and mostly play BF3 and soon BF4. No trouble with frame rate using my current setup.