Did one of the recent E D updates disable SLI? I've noticed my in space frame rate has dropped from 115 to 75. Tried updating and rolling back drivers but no change.
It was working 3 months ago as I ran extensive tests between a single card and an SLI set-up but don't let that stop you making a pointless snotty comment.
After nvidia 362.xx it never worked properly again.
Nvidia does not support it any longer, so you may see planet lighting pulsing for instance if you have horizons.