When I start up an optimize a H264 video with “make my CPU hurt” setting, the transcode seems to max out at around 8 threads. This might be okay for traditional 4 core, 8 thread systems but I’ve got a Xeon D-1541 8 core 16 thread system so it’s only using half of the CPU.
Is there a setting within plex to dictate how many threads the program SHOULD use to transcode?
You only have an 8 core CPU. Running more threads on it doesn’t make sense.
The ‘hyperthreading’ is (mostly) an additional instruction decoder, not a complete set of computation registers. Therefore it cannot contribute much to the task ‘transcoding media’.
It’s arguable how much hyper threading benefits video encoding. Some sources indicate moderate benefit, while others point to significant benefit. Regardless, Plex encoding has been shown to max out hyper threading threads on quad core i7 CPUs. How come it won’t max out 16 threads on my CPU? Is there a 8 thread max?
run multiple simultaneous transcodes, they’ll allocate to different cores (assuming your OS is any good) and you’ll get a better idea of what may be a limit and what may be HT just being crap.
ffmpeg has different core limits for different codecs for many different reasons - there are no settings you can change.
Did you ever figure this out? I am struggling with low CPU loading while transcoding on a Xeon D-1541. Plex is in an Ubuntu LXC container on Proxmox.
For example, syncing a Blu Ray rip mkv only hovers around 60%. Sync says it’s running at 7.0x speed, for reference.
