GPU use under Plex

[Enquiries]

Hey. I own a Qnap TS-873A. Have installed a GT 1030 - Gigabyte. I'm trying to understand why Plex doesn't use it when it has to transcode movies. Have all the drivers in place but the card is null, even if stream from my iphone a 4K movie via mobile network. Movie is playing ok, but the CPU is over 92% all the time. Can you give me any advice or configuration hint ?

Thanks in advance

[ed]

You may need to do this https://www.youtube.com/watch?v=RZL5hRZEEnU&t=268s