Have you tried decoding with different applications? Apple QuickTime? VLC Media Player?
This players doing decode by software mode and the system load about 100% on 720p content and lagging on 1080p.
As i know linux vaapi is using GPU shaders for the hardware decoding and they can add support for 10bit, but windows realisation of DXVA are closed source and only intel can add 10bit depth support for DXVA.
About 10bit depth you can read here:
I get these artifacts too with intel hd graphics (Core i5) , looks like all intel gpus have artifacts