Games on the Radeon 6850 would generally perform fine but seem 'jittery'. Usually didn't notice it, but sometimes it was quite obvious that you were losing frames here and there even when in non-complex situations. Of course you wouldn't notice a single one, but when it's happening every 2-3 seconds it starts being noticable when you're playing for hours. Some games were much worse than others, though I couldn't say it was directly related to how shiny the game looked. It was never big enough a deal that I did anything about it (had it for two years).
When the fan on it exploded last month and burned out the 6850 I got a GeForce 660 (no brand loyalty either way) and the issue just went away. Obviously it's a much faster card than a two year old card, but it's also noticeably smoother even with graphics cranked up to about the same FPS. It's the exact same system, that's all that changed.
Just one anecdote, but the article would explain what I was noticing (though not why).