I went through this whole fiasco with our test systems. I believe it all to be a driver issue. Using the latest amd drivers for the wx9100 fixed the issue, but you cant use the new drivers for reliable playback. Only thing I got to reliably work is windows 7. I suspect support for AMD is dead in the water and dataton hasnt addressed any of the issues.
So we are faced with the an issue now. The only thing we can reliably use are nvidia quadro cards. Any new AMD card would require newer drivers which will not work reliably.
Has anyone else had better success?