How much CPU will i need to transcode 4k to 1080p in plex? Only one stream at a time. Or would a cpu/gpu combo work best?

 

Thanks

On 4/4/2020 at 5:57 PM, david97 said:

How much CPU will i need to transcode 4k to 1080p in plex? Only one stream at a time. Or would a cpu/gpu combo work best?

 

Thanks

Unless you have a really powerful 12-16+ core CPU or dual Xeon CPUs, don't even think about 4K transcoding with a CPU.  According to Plex, a single 4K to 1080p stream takes about 17,000 passmarks vs. 2000 passmarks for a 1080p to xxxx stream.  My 8-core/16-thread Xeon has a 17,300 passmark score so I could not do even one 4K stream with pure CPU power as unRAID needs some overhead as well.

 

Here's a good read on the subject:

https://forums.plex.tv/t/info-plex-4k-transcoding-and-you-aka-the-rules-of-4k/378203

 

You'll need to do GPU transcoding if you really want to transcode 4K, and likely with a discrete Nvidia GPU and the Unraid Nvidia plugin/UnRaid build. The better recommendation is 4K content for local streaming to capable clients and a 1080p library of the same content for remote streaming and non-4K capable clients so no transcoding is required.

 

My Xeon CPU has an integrated iGPU and could probably get one transcoded 4K stream out of it, but, I have not yet tried. 

Hi,

It is better to build a powerful computer for 4K video editing based on the Intel Core i9–9900K processor. Unlike the previous model, it has not 8, but 16 threads.