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Proxmox - Plex server in Ubuntu VM not using all CPU cores

2557 Views 3 Replies 2 Participants Last post by  Prophet4NO1
I have Plex in it's own VM on my Proxmox server using Ubuntu. I have dual 2650v2 CPU's. I have run into an issue recently where I have a few movies that are in 4K only and can not transcode them on the fly down to 1080p. All movies are uncompressed MKV files. I have not had issues transcoding 1080p videos down to lower resolutions when remote streaming, but 4K to 1080p is failing with a message saying the server is not powerful enough. When I investigated I realized that the plex/ubuntu server is only using about 30% of all the CPU threads availible. In the hardware settings for the VM I have the CPU set to 2 sockets, 16 cores. This should, as I understand it, allow the VM access to all cores and threads of the dual 8c/16t server.

In Ubuntu, I can see all 32 threads. But any time I try to transcode only about 8 load up. Is this a Plex limitation or maybe something in Ubuntu? If I change the settings for the VM to 1 socket and 32 threads will the CPU look like a massive single CPU and Proxmox will deal with dividing the load? Thanks for any insight.
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I believe this is a plex limitation. I only see about 30% usage on my 3900x unRAID server whilst transcoding 4K movies. 1080p source movies usually use a lot more resources, but it depends on what audio codec the movie is using.
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