Question / Help Is OBS Studio able to use 2 CPU's?

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nikolarN

New Member
A friend of mine is selling a computer that he used in his company.

My current encoding PC specs:
Processor: Intel i7-4790K CPU @ 4.00GHz
Motherboard: MSI Z97 GAMING 5 (MS-7917)
Graphic card: AMD Radeon HD 7800 Series
Memory: 8GB HyperX 3997MHz
Storage: 60GB SSD

The PC my friend is selling:
High End Workstation Dell T7600
2 x OctalCore Intel Xeon E5-2670 32x2.6GHZ
64GB DDR3 RAM, ATI FirePro V7900
500GB SSD

I'm using an Avermedia HD C925 and i do have a Razer Ripsaw that i still haven't tested but it's an option.

Would OBS Studio be able to take advantage of all the CPU cores of both processors in the computer i'm looking to get?

I'm aiming for "slower" or "very slow" encoding so i can push the most amazing image through OBS Studio to Twitch 720p/60fps @ 3500kpbs bitrate.

How much do you think it would be of an improvement to jump from my curent encoding PC and get the PC my friend's selling? Improvement as in qualitywise towards Twitch?
 
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nikolarN

New Member
Fenrir said:
https://obsproject.com/forum/threads/dual-xeon-dedicated-stream-pc-issues.62039/

Check the discussion in this thread to understand the limitations of dual CPUs and x264.

EDIT: Also, for what it's worth, you get SIGNIFICANT diminishing returns any slower than the medium preset anyway.
Click to expand...

Okay, looking into that thread i've read this "Lots-of-slow-cores CPUs are awesome for offline/non-realtime rendering, but for realtime stuff, you're usually better going with fewer faster cores." and now my mind is kinda blown away.

Let's put it this way, i want the crispiest possible image with a C925 capture card or any other by recomendation so i can stream the crispiest, sharpest most beautiful footage 720p/60fps @ 3500kbps bitrate. :D

As far as i've read, x264 can use only 16 cores and not utilize the other CPU at all?

Not even unparking the CPU would help?
 
Mroczny_Gustaw

Mroczny_Gustaw

Member
you should revise your goal then. 720p60 requires 5500-6000 bitrate to look good. 3500 is enough only for 720p30. No amount of horsepower will change that
 
Fenrir

Fenrir

Forum Admin
Mroczny_Gustaw said:
you should revise your goal then. 720p60 requires 5500-6000 bitrate to look good. 3500 is enough only for 720p30. No amount of horsepower will change that
Click to expand...

This is actually not true at all. 720p 60fps can look great at 3500 bitrate on fast or medium preset. The entire point of using a slower preset is that video will look equivalent quality at a lower bitrate. His goal is fine, but due to the diminishing returns past medium, it's a bit optimistic.

The "bitrate calculator" that you link in your signature is actually fairly worthless, as it's not even mentioning what encoder or what preset is being used. All the tests in your linked reddit thread were performed on x264 using veryfast preset. Those settings are completely useless for anyone using NVENC, VCE, or QuickSync (to name a few other common options).
 
Mroczny_Gustaw

Mroczny_Gustaw

Member
The entire point of using a slower preset is that video will look equivalent quality at a lower bitrate.
Click to expand...
There is no way you can compensate 2k bitrate difference (5500-3500) with slower presets and have same quality on fast motion scenes. It will look better but will not compensate and will not look equivalent. This assumption is totally wrong

Fenrir said:
This is actually not true at all. 720p 60fps can look great at 3500 bitrate on fast or medium preset. The entire point of using a slower preset is that video will look equivalent quality at a lower bitrate. His goal is fine, but due to the diminishing returns past medium, it's a bit optimistic.

The "bitrate calculator" that you link in your signature is actually fairly worthless, as it's not even mentioning what encoder or what preset is being used. All the tests in your linked reddit thread were performed on x264 using veryfast preset. Those settings are completely useless for anyone using NVENC, VCE, or QuickSync (to name a few other common options).
Click to expand...


It clearly states "based or reddit post" so if someone reads with understanding what is he doing and has some basic x264 knowledge then it should be clear. If not they should not try to setup stream before some reading. But I will add this info, good catch. Anyway Im not sure on what basis you claim its useless. If someone cannot use x264 (and is constrained by twitch's 3500) then its a way to go with QSV and NVENC. These encoders perform quite well and are usable on x264's settings because they are developed with goal to look similar to x264 veryfast, you wont squeeze anything more from them anyway. I tested it - looks ok. People on this forum tested it and said its working nice. It seems to me like you dont really know what you are talking about, and repeating old myths about hw encoders. Your mod status looks very questionable to me
 
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T

TryHD

Member
even though twitch seem to have increased thier everything over 3500 kbit/s will lag for viewers policy, currently even as non partner 5000 kbit/s works fine and as partner 5700 kbit/s seems to be the limit till they will knock at your door as big partner.
Maybe they finaly realised that there are much better options for high quality streams than they were in the past.
 
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Osiris

Active Member
Mroczny_Gustaw said:
It clearly states "based or reddit post" so if someone reads with understanding what is he doing and has some basic x264 knowledge then it should be clear. If not they should not try to setup stream before some reading. But I will add this info, good catch. Anyway Im not sure on what basis you claim its useless. If someone cannot use x264 (and is constrained by twitch's 3500) then its a way to go with QSV and NVENC. These encoders perform quite well and are usable on x264's settings because they are developed with goal to look similar to x264 veryfast, you wont squeeze anything more from them anyway. I tested it - looks ok. People on this forum tested it and said its working nice. It seems to me like you dont really know what you are talking about, and repeating old myths about hw encoders. Your mod status looks very questionable to me
Click to expand...

What myths? All he's saying is that the stuff in the reddit post uses x264 and cannot be directly applied to QSV, NVENC and VCE. The quality of those encoders also differs between hardware.
 
Mroczny_Gustaw

Mroczny_Gustaw

Member
Yes applying x264 settings to hw encoders will result in lower quality, this was always clearly said.
My and the whole google sheet's point is the case when you cannot use x264 because of slower cpu. In such case applying x264 settings to hw encoder still results with good (enough) quality when you are limited by twitch's 3500. And tbh in such case there is no other way to set things up. Yes you can go below 720p but its always a tradeoff. Go below 30fps? Nope
Now Osiris, please go and count posts where people ask for settings having no idea which knob does what.....
So for x264 its very good start and if someone has no patience for more tinkering he can safely stop here.
For qsv and nvenc there is no other way - both of them are developed aiming at x264 vfast quality (seen posts of intel and nvidia devs on their forums saying that) and using its settings gives best results
I never touched VCE, no hardware
So going back to Fenrir's post, I would expect at least more assertiveness and "in the field" testing from a mod.
 
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Fenrir

Fenrir

Forum Admin
Mroczny_Gustaw said:
There is no way you can compensate 2k bitrate difference (5500-3500) with slower presets and have same quality on fast motion scenes. It will look better but will not compensate and will not look equivalent. This assumption is totally wrong
Click to expand...

Who said anything about fast motion? I stream 2D platformers at 720p, 60fps, 3500 bitrate and it looks amazing on the slow preset. Not everyone streams Overwatch or CS:GO. Your assumption there is the problem. However, I should have probably been more clear in my post. Apologies for that. Blanket statements just tend to annoy me. Please understand there's more than one use case out there, with wildly different requirements between them.

Mroczny_Gustaw said:
It clearly states "based or reddit post" so if someone reads with understanding what is he doing and has some basic x264 knowledge then it should be clear. If not they should not try to setup stream before some reading. But I will add this info, good catch. Anyway Im not sure on what basis you claim its useless. If someone cannot use x264 (and is constrained by twitch's 3500) then its a way to go with QSV and NVENC. These encoders perform quite well and are usable on x264's settings because they are developed with goal to look similar to x264 veryfast, you wont squeeze anything more from them anyway. I tested it - looks ok. People on this forum tested it and said its working nice. It seems to me like you dont really know what you are talking about, and repeating old myths about hw encoders. Your mod status looks very questionable to me
Click to expand...

I made no mention that NVENC or QSV weren't viable for streaming, just that your spreadsheet should be more clear on what data it's showing. You're touting it in your comment as having useful info, and neglect to provide the relevant details in the sheet itself, and instead ask users to go read the Reddit thread anyway making the spreadsheet kinda pointless. If you add the info and make it clear what people are looking at, it has value. I'm not trying to be rude here, just some constructive criticism. Don't take things so personally, and let's keep the personal attacks off these boards.
 
Fenrir

Fenrir

Forum Admin
nikolarN said:
Okay, looking into that thread i've read this "Lots-of-slow-cores CPUs are awesome for offline/non-realtime rendering, but for realtime stuff, you're usually better going with fewer faster cores." and now my mind is kinda blown away.

Let's put it this way, i want the crispiest possible image with a C925 capture card or any other by recomendation so i can stream the crispiest, sharpest most beautiful footage 720p/60fps @ 3500kbps bitrate. :D

As far as i've read, x264 can use only 16 cores and not utilize the other CPU at all?

Not even unparking the CPU would help?
Click to expand...

Sorry for the derailment there. As mentioned, it's really going to depend on what you're actually trying to steam. If you're going for high-motion games like shooters, you probably want to throw the FPS down to 30, even with extra CPU to spare. For lower motion games, 720p 60fps should look great at 3500 bitrate.
 
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nikolarN

New Member
Fenrir said:
Sorry for the derailment there. As mentioned, it's really going to depend on what you're actually trying to steam. If you're going for high-motion games like shooters, you probably want to throw the FPS down to 30, even with extra CPU to spare. For lower motion games, 720p 60fps should look great at 3500 bitrate.
Click to expand...
Yeah, understood.

PS. 1080p/60fps at 13000 bitrate, OH MY GOD!
https://www.twitch.tv/videos/121056458?t=01h13m24s
 
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RedM00N

New Member
I don't know about multi socket support for obs, but I'll say this.

I've ran OBS on a e5-2698 v4 I have (20 cores 40 threads) and its able to do slower/veryslow at 720 60, though it requires to bump up the thread count to a rediculous number. 1080 60 5k if I recall was doable up till slower. Anyway, You'd probably be better if with a 6950x at 4ghz+ for encoding. There should be enough data for encoding performance between those Xeons you have and a 6950x.

I've heard there is also apparently a quality decrease after 20-24 threads, but I don't think I ever noticed it even when comparing 20 vs 128 threads.
 
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