I am running on a fairly old low power computer, but I think it should be enough for direct play / direct stream. When playing UHD HEVC with Direct Play, the Plex Media Server process uses about 200% CPU (out of 400% total according to top). If I switch to Direct Stream, playback is slightly better, CPU usage is slightly lower (about 150%), and there is a new process Plex Transcoder using about 90% CPU.
I assume the Plex Transcoder process is responsible for remuxing, but I have no idea what the server process is doing with so much CPU power. I’m running the player on a recent Vizio TV. Playback is sometimes okay, sometimes choppy, and audio is delayed by a lot (~2 seconds).
The player says “throttled” which I think means the server is keeping up, so does this mean it’s a limitation of the TV?
With HD media the playback is much better although CPU usage is still higher than I expected.
The server is on gigabit ethernet, and the TV is on 802.11ng WiFi with excellent signal. My Unifi access point shows it’s connected at 144Mbps. I am wondering if this is is caused by WiFi signal issues. I don’t see any issues in the Plex log.
System specs:
Asus AT3IONT-I Deluxe
Intel Atom 330 dual core 1.6GHz CPU
4GB DDR3 memory
Storage is 3 spinning disks in ZFS raidz1
Ubuntu 20.04.1 server, minimal install
Plex Server Version#: 1.20.3.3483
Plex Player Version#: 5.4.1
Playback device: Vizio OLED65-H1
It is entirely possible that that utilization is caused by I/O when direct playing; reading that much data from disk and transferring it over the network can be a relatively expensive. I’ve got a test system with an Atom x5-z8300 (a little over twice the power of the Atom 330) and it struggles mightily direct playing 110 Mbps H.264.
Maybe it’s time I start looking at new hardware. Oh well, this machine is 11 years old so it had a good life.
I guess I could try strace on the Plex process to see what it’s doing.
Please accept that it does not meet the minimum required Passmark performance value (700) to run PMS well. Yes, it’s possible , and often done, when the values are above 500
Please consider the value for NAS systems (700) and the warnings I attach.
This Atom CPU has less than 1/2 of the PMS stated minimum.
Simple put: It cannot read the disk and send out the packets fast enough – even in a perfect playback
It is indeed time to use it for something else. It might make a fairly decent pfSense box (?) for 100 Mbps internet service.
