100% CPU with 4K to PC only

Plex Media Server Desktops & Laptops
1

I recently started collecting 4K videos instead of 1080P. I don’t have any 4K screens yet, but I figure I will soon. Whenever I try to play a 4K video on a PC, using the web browser or the Windows App (including the server itself), the CPU usage on my server immediately pegs at 100% and still stutters badly. This does not happen when I stream the same file to my Roku, where the server CPU runs between 6 and 11%. I can also watch 1080P files on the PC with no problem.

My plex server is running on a Windows 10 PC with i5-750 and 16GB of RAM, so the computer should be more than up to the task of transcoding, if it were required. My files are stored on a separate storage server. The network is not a problem as I can play the 4K source files on the server using VLC and they do not come close to maxing out the network. The server also has a GTX 1070 Ti, but while the CPU is pegged the GPU shows no encoding activity.

Settings-wise, Transcoder quality is set to auto, but I get the same results with high speed or high quality. The use hardware acceleration box is checked, although I can see no evidence that the GPU is being used. I can find no explicit Direct Play or Direct Stream settings for the web player, but Web/Quality/Home Streaming is set to “Use recommended settings.” According to the caption for this setting, compatible videos should play at original quality. However, when I play a 4K video in the web browser the quality is reported as “Convert to 2160P 4K (Maximum)”

The windows Plex app does include DIrect Play and Direct Stream settings, both of which are on. Video Quality is also set to “Original.” When I play 4K using the app, quality is reported as Original, but the server CPU still pegs at 100%.

Any help or ideas what might be going on will be appreciated.

Server Version#: 1.13.5.5332
Player Version#: (Windows app) 3.2.20-25990c77 and web browser player using Chrome

2

You’d have to post the logs… it’ll show what choices where made and why for the transcoding.

3

4K means HEVC codec.
No web browser supports it. So it must be transcoded.
I am not sure about the Windows app store app, but I guess the same applies there.

Download Plex Media Player for free below under Downloads - Apps & Devices
This should enable you to at least play them on computers in your local network.

4

Your CPU is very weak, especially if you need to transcode 4K.

Benchmark score of 3699 if you overclock it. Realistic benchmark around 3000 if you don’t.

Single Thread Rating: 1140

You can transcode 1080 with that setup, but you won’t be able to transcode 4K.

5

The plex website app does not seem to suffer the same problem as the browser and windows store app. It never occurred to me about the browser lacking support for HEVC. And, as for the windows store app, it really should support HEVC. If they’re not going to support the app, which hasn’t been updated in over a year, they really should just pull it. I assumed it was just as capable as the one from the plex website.

With this issue sorted out, trying to transcode 4k to 4k on the fly should not be necessary.

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