I think it's still a very capable CPU.
When CPU's first appeared, each generation was typically twice as fast as the last, and each time you could really see a difference. But as time has gone by the percentage increase of each release has fallen. Having compared loads of PC's it started to get difficult to tell once the performance increase went below 30%. This is when they first started to introduce benchmarks, because it was just no longer possible to tell if a CPU was faster than the previous release. I am absolutely certain that if you bench-marked a current CPU compared to the 3970 you would see a wonderful performance increase, but honestly, depending what you do with your CPU, you are pretty unlikely to actually notice a difference in real life applications. Usually there is far more to be gained by replacing the graphics card, which are still in the golden era of massive increases in performance every new release, but CPU's? No. You can happily give it a few years yet. Unless, of course, you just want ( like many people here ) to keep on the edge all the time.