My plex server (win10, G4560) could not do hardware transcoding (CPU usage 100%). BUT I found that if I login my win10 server through windows remote desktop (RDP) and keep
the conversation alive,hardware transcoding will be successfully activated. Once i closed the RDP conversation, hardware transcoding instantly gone and i get a 100% cpu usage
Hardware decoding in Windows is only allowed to apps which run in the user context. Which means that if you run Plex as a system service, you cannot use hardware decoding.
You must use “automatic user logon” after bootup and then start Plex either automatically or via the Task Scheduler.