CPU/memory questions and 4K

Plex Media Server Desktops & Laptops
1

Server Version#: 3.77.4 on QNAP TS-251 (moving to a linux instance)
Player Version#: 5.13 on Apple TV

Hi, first of all I know that i’m posting in the server-linux section even though I have plex install on a QNAP. Most of my questions here will be related to linux/hardware.

I’m currently thinking about moving to a linux server with a powerful CPU. I’m wondering what’s important for PMS, CPU core count or CPU frequency ?
I’m only doing direct play, most of the time 720p 3.5mbps. However, I would like to be able to direct play 4K content soon. That’s why I would like to move from the QNAP that already struggle with 1080p 7.5Mbps (100% CPU). Maybe in the futur I’ll do transcode play to remotely watch my content but then again it’s not my priority.

So my question is which CPU would you recommend for that usage ? I don’t want to spend more than $250 on the CPU but be straight with me if I have to spend more than that.

Also, when the video is in direct play mode, is there a cache on the file system ? For instance would it be beneficial to have Linux installed on a SSD even though the media is located on a regular hard drive ?

Finally, how many memory do you recommend ? I currently have 8Gb on my QNAP and it feel that I never use 100%. I was thinking 16Gb to be comfortable but it could be overkill.

I’ve looked at couple of thread here before posting and didn’t really find any answers.

2

Straight up… as I see it. (Others will differ)

i7-7700 will provide hardware transcoding of HEVC HDR in 4K with ease for multiple concurrent streams. IMHO, there is no visible benefit in the -8xxx or -9xxx family because they still use the same HD 6xx family graphics ASIC.

16 GB is solid if a dedicated Plex server.

NFS mount the QNAP on Linux and you will be able to pull 100 MB/sec (800 Mbps worth of video). If that isn’t enough, you need a 10 GbE LAN. (LACP won’t do more than link speed – presuming gigabit is your existing primary)

To test the HD performance of the QNAP: SSH to it then

qcli_storage -Tt

This will tell you the performance of the RAID volumes and filesystems.

3

Hi Chuck,

Thanks for you answer! I looked at the i7-7700, the passmark is 10733 for a price of $330, which for Intel looks OK to me. However, I just checked the AMD RYZEN 5 2600 and the price compare to the benchmark is amazing! I don’t have any preference between those two brands, I care more about the money than the brand :slight_smile:
From what I’ve seen, PMS support more Intel than AMD, but I didn’t find why exactly.

I don’t think I will keep my QNAP as one of my drive is not doing so well right now, I will most likely build a small HTPC server with micro ATX motherboard, SSD and a really big hard drive. I don’t need any kind of raid. Also, if at some point I need 10Gbe LAN like you said, it would be easier to upgrade with such configuration. What do you think ?

Edit1: QNAP HD TEST:

Enclosure Port Sys_Name Throughput RAID RAID_Type RAID_Throughput Pool
NAS_HOST 1 /dev/sdb 190.17 MB/s /dev/md1 Single 104.59 MB/s 1
NAS_HOST 2 /dev/sda 5.01 MB/s /dev/md2 Single 137.71 MB/s 2

The second hard drive, doesn’t look good right ?

4

With the Ryzen, there is no HW transcoding for Plex (from the internal graphics) yet.

I will soon build a Ryzen 9 3700x and will have need of an external GTxxxx GPU for Plex use.

The cost comes down to

Intel vs (AMD + GPU card)

The simplicity of the Intel in one unit.
The cost of a graphics card (and possibly power supply upgrade to run it)

1 Like
5

So basically if i’m doing only direct-play I should be fine with Ryzen, right ? Any idea when the HW transcode will be available for Ryzen or even if it’s on the roadmap ?

6

If you are only doing direct play you are fine with a raspberry pi 1. It’s basically just passing the bits along.

1 Like
7

Even with 4K HDR content ? I’m surprised because it seems that my QNAP is struggling a lot…even with 1080p 7.5mbps the CPU is always at 100% and I’ve configured direct-play for local.

8

Did you check if it is actually direct-playing?

1 Like
9

I was on my way to check the logs after your answer and I saw this “Videos with subtitles cannot be played directly.” I have been using Plex for many years with subtitles, I never had any issue so now I guess that my QNAP is actually transcoding.
Is that for all subtitles ? I supposed embedded subtitles doesn’t need transcode but subtitles “on the side” (srt or ass) need transcode ?

10

If this helps provide some info.

  1. My backbone is 10 GbE
  2. Individual devices are 1 GbE
  3. Server is currently on the i7 NAS but soon to be on a dedicated machine also at 10 GbE.

The QNAP delivers this performance with WD Red Pro drives (cache turned off)

fio test command for LV layer: /sbin/fio --filename=test_device --direct=0 --rw=read --bs=1M --runtime=15 --name=test-read --ioengine=libaio --iodepth=32 &>/tmp/qcli_storage.log
fio test command for File system: /sbin/fio --filename=test_device/qcli_storage --direct=0 --rw=read --bs=1M --runtime=15 --name=test-read --ioengine=libaio --iodepth=32 --size=128m &>/tmp/qcli_storage.log
Start testing!
Performance test is finished 100.000%...
VolID   VolName             Pool     Mapping_Name            Throughput      Mount_Path                    FS_Throughput
1       DataVol1            288      /dev/mapper/cachedev1   1.05 GB/s       /share/CACHEDEV1_DATA         888.89 MB/s
2       DataVol2            289      /dev/mapper/cachedev2   980.00 MB/s     /share/CACHEDEV2_DATA         636.82 MB/s
3       DataVol3            290      /dev/mapper/cachedev3   85.33 MB/s      /share/CACHEDEV3_DATA         77.76 MB/s
4       DataVol4            291      /dev/mapper/cachedev4   533.50 MB/s     /share/CACHEDEV4_DATA         524.59 MB/s
[~] #

Volume 1 = SSD main QTS
Volume 2 = Main HD volume
Volume 3 = 2.5" laptop spinner for development
Volume 4 = 2.5" Samsung 860 EVO SATA-3

1 Like
11

Thanks for this Chuck! I definitely have something wrong with my hard drives… that’s fine, easy fix I guess. Does having the cache disable help for performance ?

For subtitles and direct play. I’ve read that Plex need to remux when there’s subtitles, I guess I don’t need the biggest CPU but I still need a little bit of power for remuxing in direct-streaming ?

Edit: I also think that the Plex app on my apple tv doesn’t support mkv container and that a remux is done anyway to stream an MP4, right ?

12

That is correct for the old Player, the new, Plex Pass only aTV Player, supports mkv.

Remuxing into a mp4 container costs basically nothing. Transcoding Audio costs basically nothing. The only thing that is gonna make your Nas cry is the Video.

Both your volumes are fast enough to stream from.

1 Like
13

So basically if I were to go with Plex Pass, there will be no remuxing from my QNAP to Apple TV ? But what about separate subtitles ?

14

Excuse my inquiring?

Is this correct discussion (Subtitle transcoding) for this thread?
I think you’re accidentally merging?

1 Like
15

Coreection, that is broken. md1 and md2 seem fine
About subtitles i have no idea. I just now tried external subtitles and they direct played but dashboard said “no subtitles” but they were shown on TV.

1 Like
16

@Orko

To which topic do you think you’re replying ?

1 Like
17

@Chuck: My question on subtitle is relevant to my first question about CPU power though. If I need more power because I can’t direct-play with separate subtitles. I can start another topic, that’s fine but IMO, both topics are relevant for my CPU question, don’t you think so ?

@Orko: Ok thanks I’ll run some testing.

18

@ChuckPa I was not talking to you, i was replying to jinthoa, sorry if that was not clear.
Please read the last few posts for context.

1 Like
19

To bring it back to the original question, during a transcode, audio processing is limited to one CPU core.

20

@pl_5309 : To one CPU or one CPU core ?