@dgs57,
Thats really strange, I have Z97 Motherboard with i7 4790K CPU and have no issues, there is not much difference between my Haswell system and yours except i'm now running a Vega 64 dGPU. However before the Vega 64 I was running a Nvidia GTX 980 Ti and the system still had no issues with hardware encode/decode so I don't think your dGPU has anything to do with it.
I'll fire up my Haswell system and do a compare to your Clover config and see if i can spot anything, i'm using my laptop away from home right now so won't be able to do it until later ....
Cheers
Jay
Update: I actually have a copy of the EF folder from my Haswell System on my laptop so I checked for any differences in config.plist .. the only things I have enabled which you don't is FixRegions and FixMutex :-
View attachment 385816
Don't know if that will help but worth a shot.
You are also missing a critical SSDT Hot-Patch that spoofs Darwin as Windows 2015 copy the attached file into /EFI/Clover/ACPI/patched .. it might help.
Thats about all I can really suggest ....
Cheers
Jay