As already posted in other threads, it does not have anything to do with codecs or even the splitters/readers. This problem occurs regardless of what codec is in use.Just checked, i'm using 9.7 on htpc and it's running perfectly. (Powercolor HD4670 1GB PCI-E)
instead of changing video drivers, i would be using graphedit to see what codecs are in useage.
The problem occurs with any HD content. In one case it even occurs with any video content, though he hasn't confirmed yet, that reverting back to 9.6 helped. But yeah, maybe the MPC codec should be preferred for DXVA anyway. I haven't tried it for that lately. Without DXVA I prefer CoreAVC.well pdvd is not good for mkv rips, so if u want dxva you must use mpcvideodec.
but yeah if 9.6 works for you, dont upgrade, no need to change a working system, resist the urge to tinker!