No your i7 2600 should be in no way bottlenecked for gaming with a GTX 970 unless gaming at <90 FPS and even then the bottleneck would be quiet small (ie 10-15 fps against a skylake based set-up with equal clock speed). People worry about CPU power way to much on toms in regards to gaming. I still run a i7 3930k with 2 GTX 1080s for a 4K setup for example. Your CPU should be good for another generation or two of CPUs before it becomes a real hinderance.