Enabling CUDA?

I have a video converter that just updated to include Nvidia CUDA support and I was pleased that my conversions might be sped up by lots…not so. Ran the same conversion with it enabled in the Xilisoft converter and a run disabled and there was absolutely no difference. I also monitiored my GPU temps and GPU usage with EVGA Precision and there were no temps changes and the usage for both cards remained at 0%. I also have DVDFab and it boasts support from either CUDA or Physx and have never seen no speed changes in that application either.

I have 2 8800 GTS (G92) in SLI…do I need to disable SLI for CUDA to work? The Nvidia control panel of course has no options or setting for CUDA so I assume that is enbled all the time. If anyone has ideas as to why I see no speed changes please educate me.

EDIT: Nevermind…there are certain specific video output types you have to select for CUDA to be active.
EDIT2: Ok tried it…screen flickered and the conversion failed right away. Tried again and no flicker but still fails. I’ll guess Xilisoft might not have it right yet or it just won’t work for me.