I bumped into this while looking for news of GEX Europe. It seems it has helped a few people with stutters. I intend to try it but haven't got round to it yet. It seems that Nick is endorsing it so it must be good:
It seems to be an external FPS limiter that works better than the internal one. The internal slider must be set to unlimited. I must admit that in my Quad I get much better FPS when I set the FPS to unlimited ingame but I do get stutters so this might be the answer. I'll try it and let you know the results.