I am not sure this is the correct place to post this but having looked through this article Is Plex Media Server on a NAS Right for Me? I clicked the link listed as How are Direct Play, Direct Stream and Transcoding different?, which took me to a dead link .
I just wanted to report this in the hope it will be fixed.
Thank you for the report!
I have forwarded this to the right people.
For the time being, I recommend you to go here: https://support.plex.tv/articles/categories/plex-media-server/direct-play-direct-stream-transcoding/
@OttoKerner thanks for getting back to me, and for passing that on.
I will have a look at the article you have linked to. 
