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Upgrading CPU for Plex Server to handle 4K X265

MG42Maniac

MG42Maniac

MG42Maniac

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Lymington
Hi Guys,

After a bit of advice regarding upgrading the CPU in my Plex Server. It is currently a 4670K @ 4.2GHz. At the moment it is fine and handles everything. All local streams are to a B6 OLED in the lounge and UH770 in the bedroom, so direct stream. However, my 4K collection is growing and it's pegging my CPU whenever someone remotely tries to transcode down to their client. I'm thinking that the following are the most viable options:

1) Upgrade to a 4790K. Sell 4670K. Total cost would be about £50/£60.
2) Upgrade to Ryzen 1700. Sell 1150 kit. Total Cost would be about £450ish, I think.

Obviously, the first option would be preferred as it's significantly cheaper, is it going to benefit me much though? I know that the Plex transcoder will use HT, max it out in fact. I don't want to upgrade and then find it's not enough of an upgrade.

Ryzen will be a strong performer and definitely more future proofed but I don't know if I can be arsed with a full system strip down and then rebuild, especially if the i7 would be sufficient.

In terms of use cases, worst case scenario would be 2 x x265 rips (~60GB) down to 720p 4mbps stereo.



TL;DR Anyone doing much transcoding with high bitrate 4K content? i7 holding up well? Ryzen any better?
 
I don't use Plex but have plenty of experience with ffmpeg. My weak little 5557u decodes a 1080i TV signal, deinterlaces it, encodes it using x264 and splits it into 2 second chunks in a mpeg2-ts container then streams it using HLS. It uses less than 10% CPU. Even if 4k was 4x slower it wouldn't cause much trouble for my little laptop spec dual core.

Are you sure plex is using hardware encoding? In ffmpeg, switching from software x264 (libx264) to hardware (vaapi) reduces CPU usage from 80% to less than 10%... And it's transcoding, deinterlacing and chunking the video...

Edit: I should probably add that gstreamer did the same thing with about 5% CPU usage but the deinterlacing created artifacts so I swapped to ffmpeg, slower but better quality

And that I'm also transcoding audio to aac from ac3
 
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@Tom B The OP is talking about H265 though, not H264. As you'll know H265 is much more computationally intensive. OP, I don't know a lot about Plex but have you considered adding a capable gfx card instead? A 1050TI mini (eg Zotac) or Radeon 460 would handle x265 in hardware without needing to change the CPU. It may balance out the cost to change for you if the case can take it. They don't even need a PSU connector, with a TDP of 75w the mobo's PCI-e slot alone is enough. I swapped my 380 for a 1050TI for this reason, enabling hardware encoding and decoding of x265 and VP9 on an older system. You're looking at £80 to £100 for one, so it's not terrible and the size is HTPC friendly.
 
Rainmaker said:
@Tom B The OP is talking about H265 though, not H264. As you'll know H265 is much more computationally intensive. OP, I don't know a lot about Plex but have you considered adding a capable gfx card instead? A 1050TI mini (eg Zotac) or Radeon 460 would handle x265 in hardware without needing to change the CPU. It may balance out the cost to change for you if the case can take it. They don't even need a PSU connector, with a TDP of 75w the mobo's PCI-e slot alone is enough. I swapped my 380 for a 1050TI for this reason, enabling hardware encoding and decoding of x265 and VP9 on an older system. You're looking at £80 to £100 for one, so it's not terrible and the size is HTPC friendly.
Click to expand...
I did exactly the same thing with my HTPC. A little bus-powered 1050 does all the decoding in hardware leaving the i3 Haswell processor snoozing at <10%
 
r22snapper said:
I did exactly the same thing with my HTPC. A little bus-powered 1050 does all the decoding in hardware leaving the i3 Haswell processor snoozing at <10%
Click to expand...

I assume that hardware decoding is good for just a single stream? If so, OP would like to cater for two concurrent transcodes. I've not played with Plex GPU decoding to be fair.
 
I'm thinking that a second version may be a better bet, if the original is 60GB, then an extra 2.5GB for an optimised version is nothing. I will take a look at GPU based transcoding, would want a GPU that had a low power consumption though.
 
MG42Maniac said:
I'm thinking that a second version may be a better bet, if the original is 60GB, then an extra 2.5GB for an optimised version is nothing. I will take a look at GPU based transcoding, would want a GPU that had a low power consumption though.
Click to expand...
Very true; keep us posted. I'm interested to hear how you get on.
 
Rainmaker said:
@Tom B The OP is talking about H265 though, not H264. As you'll know H265 is much more computationally intensive. OP, I don't know a lot about Plex but have you considered adding a capable gfx card instead? A 1050TI mini (eg Zotac) or Radeon 460 would handle x265 in hardware without needing to change the CPU. It may balance out the cost to change for you if the case can take it. They don't even need a PSU connector, with a TDP of 75w the mobo's PCI-e slot alone is enough. I swapped my 380 for a 1050TI for this reason, enabling hardware encoding and decoding of x265 and VP9 on an older system. You're looking at £80 to £100 for one, so it's not terrible and the size is HTPC friendly.
Click to expand...

H265 isn't very useful for streaming as most clients wont support it, I gathered what he said he was transcoding from H265 content to H264 so that clients can play it more easily. If the original files are H265 and the stream is H265, then you don't need to transcode anyway. Just stream without conversion, very low CPU usage.

Which is another option that most streaming websites do. If you have the storage space (which is cheaper and more extensible than a new CPU), transcode the original file once to a format that can be streamed without further transcoding. HLS, for example, allows you to specify different bitrates within the same stream. The user (or their browser) then selects the stream their connection can handle. That way, you store the original video.mkv, video.m3u8, video.720p.m3u8, video.1080p.m3u8 and the .ts chunks that belong in the playlists. Transcoding happens once, you can then serve as many clients as your bandwidth allows.

As I said, I don't know how Plex works but have set up websites that stream video and have a HTPC streaming video/TV.
 
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Tom B said:
H265 isn't very useful for streaming as most clients wont support it, I gathered what he said he was transcoding from H265 content to H264 so that clients can play it more easily. If the original files are H265 and the stream is H265, then you don't need to transcode anyway. Just stream without conversion, very low CPU usage.
Click to expand...
My Galaxy S5 can decode HEVC at typical phone resolutions and bit rates (I think I was trying 720p @ 1.5 Mb/s) and that is rather old these days. The problem was my TV server CPU not being able to keep up! If only I'd gone for the i7-4770 instead of the i5-4440 when I built it. Ah well.
 
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I've had another 6TB Red delivered so I am going to try having the original 4K HEVC copy and a 2GB x264 "streaming edition". I will update with my findings.
 
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