I would humbly suggest a simple thing for starters.

If I got it right, the 30FPS might be down to an issue with nvidia card.

Why not lock it at 30fps if nvidia card is the main Graphic card?

And then allow for an unlock in the option if the users have an ATI as the main card.

Granted, it would not be a final fix, but at least, it would maybe fix the issue for Ati/AMD users smile.