Re: 97.46 fc6 x86_64 DPMS, XVideo, etc. issues
I believe that xv support is in the driver itself. DPMS is part of the core X server bits.
I'm not sure how you've reconfigured this system, but at this point, I'd suggest either backing out the changes one at a time until you determine what caused this, or starting with a fresh install, and testing after each change. Either way, it seems unlikely that this is an nvidia driver bug, and even if it is, I'd need you to provide me with details on how to replicate it.