Ok, somebody has to ask crazy questions around here, and I guess that has to be me.
It looks like Haswell will decode 8K H264 bitstreams, but with the MFX_WRN_PARTIAL_ACCELERATION, warnings, and quite possibly all in software. Meaning there is a Huge performance drop relative to decoding 4K. [in terms of output pixels/persec or output GB/sec, not FPS]
[I get about 250fps decoding 4K H.264 with Haswell, but about 12fps decoding 8K H.264 with Haswell]
Can Skylake decode H.264 8K (7680x4320) without MFX_WRN_PARTIAL_ACCELERATION?
Cam