I just realized how fast my Intel I9 with 64 gigs would convert a file. Just decided to uninstall it from the I5 with only 8 gigs of ram. I’, actually seeong close to a 90% faster conversion. Could also be attributed to the hardware acceleration using the Nvidia Geoforce RTX 2060 Super.
It is the RTX 2060 doing the majority of the work, but you could probably get better quality if you just did --CPU-- only. Most people are running GTX 1050 1060 (Pascal) with a relatively weak CPU like i3 or i5 so they benefit a lot by using their GPU. This is the cheapest solution I have found that allows 50-60 conversions daily and gives you enough --CPU-- leftover to surf the web or run Blue Iris / Plex Server. I bet your --CPU-- could do H.264 super fast without GPU.