I’m about to buy a new server for PMS. But im unsure of what to buy.
I’m currently running a 2012 mac mini and find it incredibly reliable.
But now im aiming for something that can transcode 4K. And is able to run about 4–5 transcodes at the same time.
At the moment it wont be more than 1-2 4K transcodes at the same time. But i want it to be future proof, so if it can handle 4-5 4K transcodes that would be great. But it need to handle 4-5 transcodes in total (1080p and 4K).
Suggestions?
I doubt any current processor could transcode 4-5 streams simultaneously.
At least I doubt I could afford one
I have to second @jjrjr1. Transcoding 4K per se is a very broad term. What are you talking about specifically. There might be a x264 file in 4K resolution with a bitrate ranging from 10’000 kbit/s up to 90’000 kbit/s, you might have a x265 file with smaller bitrates but comparable quality etc.
When it comes to 4K transcoding I guess your best bet at the moment is to have gpu-accelerated transcoding which plex offers. Bearing that in mind, gpu accelerated transcoding depends on the capabilities of the gpu (I am not only talking raw power, but support for specific codecs (x264,x265 within a range of resolutions and bitrates) and the software implementation.
For instance I have an Intel Skull Canyon Nuc with an i7-6770HQ. This processor has a passmark of around 9’500. That is from my experience barely enough to have one x264 high bitrate 4K transcode when nothing else is going on. However the Skull Canyon Nuc has an intel iris pro 580 gpu. This gpu is able to decode and encode x264 and even x265 up to 8 bit. But it isn’t able to encode or decode x265 10 bit (sometimes called HDR).
What this means with Plex enabled GPU accelerated transcoding: I can easily transcode a 4k x264 Video and have room to spare for another 2 or 3 1080p transcodes. Hovewer if I would throw a x265 10 bit high bitrate video at my computer it would really struggle.
Since CPUs available to consumers for a reasonable price don’t have the necessary raw power yet to transcode multiple instances of 4K video there seems to be a shift towards GPU encoding/decoding. But that depends heavily on your GPUs capability.
So long story short: There is no easy answer to your problem. You need to be aware of the fileformats you have and will have (most likely x264 and x265 up to 10bit), you need to have the correct software support for your GPU (I don’t even know if Plex supports x265 gpu accelerated transcoding yet? EDIT: it apparently does since recently up to10 bit (forums.plex.tv/discussion/297309/10-bit-hw-transcoding#latest) and you need a fairly modern GPU. This is going to give you the highest probability of being able to support multiple 4K transcodes. However, all the information above comes with the disclosure that I haven’t really invested a lot of time in reading into the matter. So take it up on yourself to do that. You might also want to make sure the GPU supports multiple instances of transcoding!
Ok, sounds like I should ditch the 4k transcoding for now. 
How about if I want to stream the 4k video to a device that doesn’t need to transcode it? Like locally. To one device only. And like 4 transcodes up to 1080p only at the same time (and same time as 4k video stream)
4 transcodes in 1080p require a passmark score of 2’000 per transcode support.plex.tv/hc/en-us/articles/201774043. Bearing in mind that is full software transcoding. If you get a supported intel cpu with integrated graphics and quicksync less might be working as you can use the integrated gpu for hardware accelerated transcoding (assuming your 1080p file is in a supported format, which probably most of them are). If you have a 4K file that can direct play (you have to be sure about that!) on the device you watch, it will barely use cpu on your server. The server basically passes through the file. The only thing you need is a decent connection from the place you store the file to the server and furthermore from the server to your client.
Ok, would a intel nuc 7i7bnh be good for that? Or is there something better suited?
The mentioned nuc has a passmark of around 6’500, so I guess you would be able to have 3 transcodes. The iris plus 650 onboard gpu is roughly the same performance wise, as the iris pro 580 my skull canyon nuc has. So it will take another 1 or 2 transcodes I guess. Just be aware that if you transcode with hw-acceleration below 720p the quality gets a lot worse compared to software transcoding.
I guess the intel nuc 7i7bnh would be an okay choice. However, for the price of a well equipped intel nuc kit (at newegg with 8 GB DDR 4 and 512 GB SSD, 850 USD at the moment) you probably could build a more powerful system yoursefl, if you don’t need the small form factor.
Small form factor, especially vesa mount, was a buying decision for me. That’s the reason I have a nuc.
Ok, the form factor isn’t an issue.
I just want the best hardware possible for plex with the demands I’ve got. So if building my own is the way to go I think that’s what I should do.
Not sure which cpu and graphics (or built-in on the mobo) I should choose though.
Well that heavily depends on your budget 
; Generally speaking Ryzen offers more passmark per dollar but has no integrated gpu. A full fledged i7 quadcore would probably be a good idea, alternatively you could also consider used server grade xeon processors that come at a reasonable price.
Regarding HW-accelerated transcoding: Nvidia Consumer Graphics Cards offer 2 hw transcodes (driver limit); Quadros might support more? (I am not sure about this so you need to read up on this issue yourself) ; QuickSync (Intel integrated GPUs) don’t have a driver limitation but are generally less powerful compared to a dedicated GPU.
You should find some inspiration over there: reddit.com/r/PleX/search?sort=new&restrict_sr=on&q=flair%3ABuild%2BAdvice
you could also do something like this: pcpartpicker.com/b/BLP323
EDIT: This pcpartpicker.com/list/MJrvHNis the above pc partpicker build with current pricing and stripped down for a “plex server only” solution (meaning no storage and assuming a “free” OS).
i think im gonna go the server grade xeon way.
thanks for all the help. ill look thru those pages and see if i can choose something to build.
My current Build is (2) Xeon E-5 2697 v3 Asrock Ep2c612d16sm mother board w/ 128 gb of ram
1- Mellanox sfp+ card (10gb)
Running a ram disk at 64 gb helps out alot.
5- Seagate IronWolf 8TB NAS Internal Hard Drive HDD – 3.5 Inch SATA 6Gb/s 7200 RPM 256MB Hard Drives
Adaptec Asr72405 Raid controller (Ebay)
