GPU upgrade from 6950?
So lately, I've noticed some of the games I play on my PC run a little slow on ultra, and sometimes even on high. So I've decided to upgrade my GPU (i5 2500k shouldn't be the issue quite yet). However, I'm not sure which direction to go with my upgrade. I have about a $200 limit, possibly about $250 if the performance boost is worth the extra $50. With that being said, I currently have a Gigabyte Radeon HD 6950 1 GB OC edition. Has been a great card for its duration, and still is, considering it can run most of the latest games on high with only the slightest of stutters, but I would like to be able to run games like Black Ops II and BF3 maxxed out. So with my current graphics card and price limit, what are some good choices for an upgrade? Nvidia or AMD? Which model and why? I understand I won't get the world for free, but I would like to get as close as possible lol Thank you for any suggestions.