CPU for Plex Media Server? (4k transcoding)

voidshatter · 11 Aug 2017 at 02:19

So I've just started to look into building a home media server for Plex, and I'd like it to be relatively future-proof. Then "4k transcoding" comes in my mind, as I guess 4k may be the standard resolution for the years to come.

I have little experience in this field (as to Plex, video format, encoding, H265 etc). I've decided to do some search online, and it appears that four different people suggest that a Passmark score of around 15,000 is about to be the minimum requirement for transcoding 4k videos without stuttering.

Checking the Passmark ladder (and estimating some unlisted CPUs by simple calculations with errors), I've found the following (relatively "affordable") CPUs to be on my list (assuming no overclocking):

CPU model: Passmark score, price, 4k transcoding capability for Plex Media Server

AMD Epyc 7601: 51,207 (est.), $3139 (not really affordable!), can transcode three 4k streams concurrently
Intel i9-7980XE: 32,618 (est.), $1999, can transcode two 4k streams concurrently
Intel i9-7960X: 31,224 (est.), $1699, can transcode two 4k streams concurrently
Intel i9-7940X: 30,248 (est.), $1399, can transcode two 4k streams concurrently
AMD ThreadRipper 1950X: 26,350, $999, can transcode one 4k stream
Intel i9-7920X: 24,255 (est.), $1189, can transcode one 4k stream
AMD ThreadRipper 1920X: 23,200 (est.), $799, can transcode one 4k stream
Intel i9-7900X: 23,068, $999, can transcode one 4k stream
Intel i7-7820X: 19,159, $600, can transcode one 4k stream
Intel i7-6900K: 17,980, $999, can transcode one 4k stream
AMD ThreadRipper 1900X: 17,211 (est.), $549, can transcode one 4k stream
AMD Ryzen 1800X: 15,419, $419, can transcode one 4k stream
AMD Ryzen 1700X: 14,663, $325, may stutter
Intel i7-8700K: 14,577 (est.), $350, may stutter
Intel i7-8700: 14,452 (est.), $312, may stutter
AMD Ryzen 1700: 13,816, $270, will stutter

It appears that the Ryzen 1800X is the minimum buy, and its 95W TDP is probably the coolest viable option. The price-performance ratios of the AMD CPUs do look more attractive. And an advantage of these AMD CPUs would be the unofficial support of ECC memory modules (yeah, without 3600C16 or 3200C14 there will be a performance hit).

The advantage of the Intel CPUs? ASRock has a mini-ITX motherboard offering four SO-DIMM DDR4 memory slots, presumably supporting 64GB? The Lian-Li Q33/Q34 ITX case will be able to hold a cooler as tall as 180mm, and a 520W fanless PSU from Seasonic. Going for AMD probably means memory capacity will be limited to 32GB for ITX builds for now.

Coffee Lake 8700K, 8700 and Ryzen 1700X, 1700 are not so good choices for this job, as they are just close to the edge of stuttering.

Any thoughts?

HEADRAT · 11 Aug 2017 at 06:35

My thoughts are why are you trancoding 4K video on the fly, wherever possible you should be direct steaming.

Why not just use the optimise feature to create a video file that can be played by clients that aren't able to direct stream 4K h265

Hard disc space is much cheaper than a big CPU with all the heat/power/noise that it will end up bringing to the Plex Server.

Doobedoo · 11 Aug 2017 at 07:27

I know nothing about 4k transcoding but Ithink you may have got your numbers wrong

voidshatter · 11 Aug 2017 at 07:42

HEADRAT said:
My thoughts are why are you trancoding 4K video on the fly, wherever possible you should be direct steaming.

Why not just use the optimise feature to create a video file that can be played by clients that aren't able to direct stream 4K h265

Hard disc space is much cheaper than a big CPU with all the heat/power/noise that it will end up bringing to the Plex Server.

I just don't like the fact that I have to wait for optimisation first... Sometimes I just want to watch it straight away

voidshatter · 11 Aug 2017 at 07:44

Doobedoo said:
I know nothing about 4k transcoding but Ithink you may have got your numbers wrong

Whenever a score can be found at Passmark's website, I take it with higher priority than the estimated value at cpu-monkey's. There are errors for sure.

HEADRAT · 11 Aug 2017 at 07:53

voidshatter said:
I just don't like the fact that I have to wait for optimisation first... Sometimes I just want to watch it straight away

Fair enough but you will have to pay dear for your impatience

I've always found Plex's transcoding to be problematic, it's never seems as smooth as a directplay.

You really will be taking a sledgehammer to crack a nut.

voidshatter · 11 Aug 2017 at 08:17

HEADRAT said:
taking a sledgehammer to crack a nut

Perhaps the Ryzen 1800X won't be generating too much heat or noise, since I can use the Thermalright Le Grand Macho RT CPU cooler as a fanless solution, in conjunction with Seasonic's 520W/460W fanless PSU?

95W for 24x7x365 translates to £133 per year at Southern Electric's current tariff inc VAT. I don't think I can be transcoding all year

Intel CPUs may be more problematic as I would need to do delidding, and I can't use a fanless solution.

HEADRAT · 11 Aug 2017 at 09:38

Wel

voidshatter said:
I don't think I can be transcoding all year

No but surely you'll want to leave the Plex Server running 24/7?

As above I've never really thought the "on the fly" transcoding was all that special so I've always gone down the route of directplay or optimize which has always seemed much more palatable.

DragonQ · 11 Aug 2017 at 10:11

If it's just for streaming can you not use GPU acceleration? Not as good quality but much cheaper.

Otherwise 1950X looks a good shout. Despite x265 not scaling linearly with cores at such high core counts, it should still be the fastest option. Example.

HEADRAT · 11 Aug 2017 at 10:28

A 1950X just seems to be a bonkers amount to spend when Plex can automatically optimise media (or new media as it's added)

https://support.plex.tv/hc/en-us/articles/213095317-Creating-Optimized-Versions

moogle · 11 Aug 2017 at 10:45

HEADRAT said:
Fair enough but you will have to pay dear for your impatience I've always found Plex's transcoding to be problematic, it's never seems as smooth as a directplay.

You really will be taking a sledgehammer to crack a nut.

What is your plex server running on? Ever since I changed my transcode path to memory it's been super smooth.

pepp77 · 11 Aug 2017 at 10:48

Or you could look into buying a Roku4 that will allow H265 4k streams to direct play I believe.

HEADRAT · 11 Aug 2017 at 10:59

Does the v2 of Shield TV work as well with DirectStream, I don't have a 4K TV so I've never really looked into it.

muon · 11 Aug 2017 at 11:14

When did Passmark represent transcoding?

As other have said, why would you be transcoding 4K to 4K on the fly? Seems bizarre as it won't be lossless.

Panos · 11 Aug 2017 at 12:55

voidshatter said:
So I've just started to look into building a home media server for Plex, and I'd like it to be relatively future-proof. Then "4k transcoding" comes in my mind, as I guess 4k may be the standard resolution for the years to come.

I have little experience in this field (as to Plex, video format, encoding, H265 etc). I've decided to do some search online, and it appears that four different people suggest that a Passmark score of around 15,000 is about to be the minimum requirement for transcoding 4k videos without stuttering.

Checking the Passmark ladder (and estimating some unlisted CPUs by simple calculations with errors), I've found the following (relatively "affordable") CPUs to be on my list (assuming no overclocking):

CPU model: Passmark score, price, 4k transcoding capability for Plex Media Server

AMD Epyc 7601: 51,207 (est.), $3139 (not really affordable!), can transcode three 4k streams concurrently
Intel i9-7980XE: 32,618 (est.), $1999, can transcode two 4k streams concurrently
Intel i9-7960X: 31,224 (est.), $1699, can transcode two 4k streams concurrently
Intel i9-7940X: 30,248 (est.), $1399, can transcode two 4k streams concurrently
AMD ThreadRipper 1950X: 26,350, $999, can transcode one 4k stream
Intel i9-7920X: 24,255 (est.), $1189, can transcode one 4k stream
AMD ThreadRipper 1920X: 23,200 (est.), $799, can transcode one 4k stream
Intel i9-7900X: 23,068, $999, can transcode one 4k stream
Intel i7-7820X: 19,159, $600, can transcode one 4k stream
Intel i7-6900K: 17,980, $999, can transcode one 4k stream
AMD ThreadRipper 1900X: 17,211 (est.), $549, can transcode one 4k stream
AMD Ryzen 1800X: 15,419, $419, can transcode one 4k stream
AMD Ryzen 1700X: 14,663, $325, may stutter
Intel i7-8700K: 14,577 (est.), $350, may stutter
Intel i7-8700: 14,452 (est.), $312, may stutter
AMD Ryzen 1700: 13,816, $270, will stutter

It appears that the Ryzen 1800X is the minimum buy, and its 95W TDP is probably the coolest viable option. The price-performance ratios of the AMD CPUs do look more attractive. And an advantage of these AMD CPUs would be the unofficial support of ECC memory modules (yeah, without 3600C16 or 3200C14 there will be a performance hit).

The advantage of the Intel CPUs? ASRock has a mini-ITX motherboard offering four SO-DIMM DDR4 memory slots, presumably supporting 64GB? The Lian-Li Q33/Q34 ITX case will be able to hold a cooler as tall as 180mm, and a 520W fanless PSU from Seasonic. Going for AMD probably means memory capacity will be limited to 32GB for ITX builds for now.

Coffee Lake 8700K, 8700 and Ryzen 1700X, 1700 are not so good choices for this job, as they are just close to the edge of stuttering.

Any thoughts?

Why you jump from 1950X to 7601?
there is the 7401 for $1100 and 24 cores. And 7551 for $2100, a 32core cpu

ZXSpectrum · 11 Aug 2017 at 13:43

I would say grab a couple of second hand Xeon E5-2670 CPUS, C602 motherboard and 16Gb DDR3 ECC Reg and you should be golden. The CPUs should cost you about £50 a piece, the memory about £30 and the board about £300. Although old tech it will be rock solid and have incredible transcoding performance. I have a single 2670 and that works mint.

HEADRAT · 11 Aug 2017 at 13:58

I wonder how a:

Super Micro X8DTI-F Motherboard
80GB RAM (ECC Registered DIMMs)
2 x Intel Xeon x5675 (3.06 GHz)

Would fair with 4K Transcode

ZXSpectrum · 11 Aug 2017 at 14:05

I would say that would work fine! I am a big advocate of utilising older tech for home media server use, I have a fully stacked Xeon system 8 core 16 thread 2.6Ghz (Turbo to 3.3) 16Gb of DDR3 1333Mhz ECC Reg, Intel S2600CO4 motherboard, Intel 4U Pedestal/Rackmount Chassis and a Intel Server 500W PSU. Granted I did get some parts for nothing as they are old tech but even so they make fantastic, stable servers that can be utilised for a variety of home server use and are reasonably cheap.

HEADRAT · 11 Aug 2017 at 14:10

Yeah I swapped some stuff for the above but I've never really used it in anger, the challenge was sourcing the bits and building it, after that I kinda lost interest

I'm like a Magpie when it comes to computer equipment, Mrs HEADRAT makes me "purge" it all from time to time!

voidshatter · 11 Aug 2017 at 14:44

DragonQ said:
If it's just for streaming can you not use GPU acceleration? Not as good quality but much cheaper.

If I want to stream over the local network, not via the output cable of a graphics card, will GPU acceleration work?