I came across this thread a moment ago and after doing exactly the same as suggested im running at a smooth 50-60fps and it looks AMAZING (also this fixes the shadow problem)
Rather than set the gfx options through skyrim itself do it through CCC and you should see a massive difference in quality and performance.
http://www.tomshardware.co.uk/forum/332396-15-6950-issues-skyrim-possible-solution-inside
I assume nvidia cards have a similar frontend for changing gfx settings on the card rather than in game and if so can you let me know if this helps you!!
IF THIS DOES HELP YOU GIVE THE THREAD A BUMP TO KEEP IT AT THE TOP

HOPE THIS HELPS THIS GAME IS BEAUTIFUL
Love love and more love,
Acid.



