I made another attempt at using VT-d for my cameras by going with Zoneminder under Linux. This actually worked and seemed to work ok but I really dislike Zoneminder! I tried Motion and kMotion instead and the good news is it works...for longer. I'm still having problems with kernel crashes after a day or two. It's encouraging but I'm not sure I want to fuss with it anymore. Maybe I'll try Zoneminder one more time just in case the kernel wants to behave.