Nothing is ""Overkill". That "Overkill" hardware of today is useless piece of junk tomorrow. And with Dynamic Super Resolution even GTX 980 can't do the job. Not by a mile and a half (unless it's a very old game and for that it's perfect). Enable Triple Buffering and your PC commits a harakiri...
If you run out of VRAM all the hell breaks loose. Or at least your game becomes a slide show. Your FPS comes down from what ever it was to somewhere round 2-5.
If this problem occurs, bring down the AA setting. That takes a lot of VRAM. Do not touch the lately released (while typing this) MSAA...