Oh I am not denying the efficiency of it, I am simply saying that any modern hard drive, that is not already overloaded, has plenty of iops to cover any plex transcoding tasks.
If a hard drive can not keep up with whatever any servers load of users/transcodes, then there are bigger problems at play.
Otherwise, the main bottlenecks will be either the internet bandwidth between server/client, and the server cpu (or gpu) in older/under powered servers (ie trying to serve too many users, or trying to decode HEVC).
Your OS, regardless of windows/linux, will have disk caching for the transcoder, which will automatically absorb the io of transcoding and other io loads.
There is a few old thread here on this forum which tested transcoding to ram extensively.
for starters
