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Windows 10: audio dropouts on multi-core CPU setups

Posted: Wed May 10, 2017 9:55 am
by Fabio Bartolini
Hello everyone,

I thought it might be useful to link this KB article on the Forum, as this might negatively affect quite a few users using i7 Extreme and Xeon setups.

Please, see here:
https://helpcenter.steinberg.de/hc/en-u ... CPU-setups

Kind regards,

[Edit: Specifications of your Intel CPU can be found here: https://ark.intel.com/]

[Edit 2: If you have drop-outs and are using a 2, 4, 6, 8, 10 or 12 core CPU, using the audioengine.properties files won't help in any way, please start trouble-shooting here: https://helpcenter.steinberg.de/hc/en-u ... s-for-DAWs - related articles: https://helpcenter.steinberg.de/hc/en-u ... ASIO-Guard and https://helpcenter.steinberg.de/hc/en-u ... and-Nuendo - if all fails, please contact Support via MySteinberg]

Re: Windows 10: audio dropouts on multi-core CPU setups

Posted: Wed May 10, 2017 12:08 pm
by vinark
Interesting Fabio! But can you explain a little bit more? What is the relation between the 32 processes which can run in MMCSS and 14 cores? Or is it 32-4 (as mentioned in the article) is 28 and cubase needs 2 audio processes per core?
Thanks!

Re: Windows 10: audio dropouts on multi-core CPU setups

Posted: Wed May 10, 2017 1:05 pm
by Fabio Bartolini
Hi,

I don't actually know how deep I can delve into the details, sorry.
I'll check and post back.

Re: Windows 10: audio dropouts on multi-core CPU setups

Posted: Wed May 10, 2017 3:30 pm
by xanthos84
For me, it does not fix any of my cpu spikes when using VST synths.

Re: Windows 10: audio dropouts on multi-core CPU setups

Posted: Wed May 10, 2017 3:47 pm
by vinark
Will only help if you have 8 cores with hyperthreading or 16 cores (or more) if I understand it correctly.

Re: Windows 10: audio dropouts on multi-core CPU setups

Posted: Wed May 10, 2017 4:26 pm
by Fabio Bartolini
@xanthos84: if you use the i7 6700k as per your post here viewtopic.php?f=253&t=117107&p=637251#p637251 this article does not apply to you in any way.

@vinark: exactly, the issue will only affect systems using CPUs like i7-6950X, Xeon with more than 14 cores and of course dual Xeon configurations.
And yes, Cubase spawns 2 threads with MMCSS priority per core, plus the 4 used for non-audio.

Re: Windows 10: audio dropouts on multi-core CPU setups

Posted: Wed May 10, 2017 5:44 pm
by AlakaLazlo
Is this applicable to i7-5820 processors?

Re: Windows 10: audio dropouts on multi-core CPU setups

Posted: Wed May 10, 2017 6:20 pm
by eli_lilly
Thanks, I haven't had an issue with dropouts at all, but may explain why I get better performance when HT is disabled.

-E

Re: Windows 10: audio dropouts on multi-core CPU setups

Posted: Wed May 10, 2017 7:06 pm
by Rommelaar
Fabio, thanks for the information.

I assume Steinberg has notified Microsoft (Peter Brown) regarding this issue, right?

Re: Windows 10: audio dropouts on multi-core CPU setups

Posted: Wed May 10, 2017 7:49 pm
by Fabio Bartolini
For those who don't know their CPU has more than 14 cores, on https://ark.intel.com/ you can find specifications for all Intel CPUs. AlakaLazlo, your i7-5820 is a 6 cores / 12 threads CPU, so it's not affected.

@Rommelar: We contacted the relevant parties at MS - we decided to inform the users because no short-term solution has been found.

Re: Windows 10: audio dropouts on multi-core CPU setups

Posted: Wed May 10, 2017 8:52 pm
by AlakaLazlo
Thank you Fabio. Still getting massive real time ASIO spikes and dropouts. :(

Re: Windows 10: audio dropouts on multi-core CPU setups

Posted: Thu May 11, 2017 1:10 pm
by Cat
Thank you Fabio.
I have a couple of questions, if you will be so kind:

1. My processor is Xeon 12 cores (24 threads). It is affected, right? It is still not clear to me whether we are talking about the number of cores or number of threads. I think it is the later, but I found one instance in the thread where it could mean otherwise.

2. I am running both Cubase and ViennaEnsemble Pro on this 12 cores/24 threads computer. If I use the audioengine.properties file to limit Cubase's cores/threads count, how would that impact on VEPro? I will address this question in the VSL forum as well, but does anyone know if Vienna Ensemble Pro also needs MMCSS threads? Is it a real-time (high priority) type of process, just like Cubase?


Fabio Bartolini wrote:Hello everyone,

I thought it might be useful to link this KB article on the Forum, as this might negatively affect quite a few users using i7 Extreme and Xeon setups.

Please, see here:
https://helpcenter.steinberg.de/hc/en-u ... CPU-setups

Kind regards,

[Edit: Specifications of your Intel CPU can be found here: https://ark.intel.com/]

Re: Windows 10: audio dropouts on multi-core CPU setups

Posted: Thu May 11, 2017 1:18 pm
by Rommelaar
Logical core = real core + hyperthreading

Re: Windows 10: audio dropouts on multi-core CPU setups

Posted: Thu May 11, 2017 1:56 pm
by silhouette
I run Cubase 9.0.10 on Windowa 8.1 and I have been having audio dropouts ever since upgrading to 9. I thought it was just me and am quite relied to see this thread. I would be interested to see how many users on Windows 7 and 8.1 are affected. Mine is a 6 core machine with Hyperthreading turned on and it is definitely affected - see details below. Which has not been an issue for me prior to Cubase 9.

Re: Windows 10: audio dropouts on multi-core CPU setups

Posted: Thu May 11, 2017 2:07 pm
by Rommelaar
@Silhouette:
The i7 in your signature suggest that your have a 8 core machine, capable of a total of 16 threads.

Re: Windows 10: audio dropouts on multi-core CPU setups

Posted: Thu May 11, 2017 2:22 pm
by silhouette
Rommelaar wrote:@Silhouette:
The i7 in your signature suggest that your have a 8 core machine, capable of a total of 16 threads.
You are quite right - my maths was always a little suspect. Thanks for pointing that out.

The drop outs seem to be worst for me when I have imported projects from previous versions of Cubase.

Re: Windows 10: audio dropouts on multi-core CPU setups

Posted: Thu May 11, 2017 3:19 pm
by Fabio Bartolini
@ Cat: Yes, if you have Hyper-Threading enabled, you are using 24 cores and your CPU is affected.
If HT is disabled, you don't need to worry.
The engine.properties file is not going to affect VEP in any way, as it only relates to the Cubase Audio Engine.
I don't know how VEP works internally, but it will access its own 32 threads to my understanding.

@silhouette: If you are using Windows 8.1, the issue is somewhere else, this limitation is not present in Windows 7, 8 and 8.1, only in Win 10.

As Rommelaar wrote, the limit applies to Logical cores, which includes physical and HT.

Re: Windows 10: audio dropouts on multi-core CPU setups

Posted: Thu May 11, 2017 7:17 pm
by Cat
Fabio Bartolini wrote:@ Cat:
The engine.properties file is not going to affect VEP in any way, as it only relates to the Cubase Audio Engine.
I don't know how VEP works internally, but it will access its own 32 threads to my understanding.
Aha - so in Windows 10 there is a limit on the number of MMCS threads per process. So both Cubase and VEPro will each be considered one process, each with maximum number of MMSC threads.

Another thing I don't understand: why limit Cubase to only 14 logical cores (via audioengine.properties) when it seems that the maximum number of MMSC threads in Win 10 is 32 per process.

Re: Windows 10: audio dropouts on multi-core CPU setups

Posted: Thu May 11, 2017 10:25 pm
by vinark
1 core is 2 logical cores. 4 threads are already taken so 28 left. Divide 28 by 2 for HT and you have 14 cores . If you have HT disabled you can ignore it all (unless you hae 2 16 core xeons).

Re: Windows 10: audio dropouts on multi-core CPU setups

Posted: Thu May 11, 2017 10:31 pm
by PeppaPig
Cat wrote: Another thing I don't understand: why limit Cubase to only 14 logical cores (via audioengine.properties) when it seems that the maximum number of MMSC threads in Win 10 is 32 per process.
It's all explained above and in the link, all you have to do is read it. Cubase is the "process", windows reserves 4 MMCSS threads, leaving 28, Cubase schedules two MMCSS threads per CPU core (real or logical), 28 divided by 2 is...

Re: Windows 10: audio dropouts on multi-core CPU setups

Posted: Thu May 11, 2017 10:43 pm
by Cat
"28 divided by 2 is..." .. 14! 14 what? 14 physical cores. I did this math, thank you. So are we then talking about CPU's with more than 14 physical cores that have the issue? In another place it was said that the CPU's with more than 14 logical cores have problems. Which one is it? I am so confused...Anyone could explain this, please?
PeppaPig wrote:
Cat wrote: Another thing I don't understand: why limit Cubase to only 14 logical cores (via audioengine.properties) when it seems that the maximum number of MMSC threads in Win 10 is 32 per process.
It's all explained above and in the link, all you have to do is read it. Cubase is the "process", windows reserves 4 MMCSS threads, leaving 28, Cubase schedules two MMCSS threads per CPU core (real or logical), 28 divided by 2 is...

Re: Windows 10: audio dropouts on multi-core CPU setups

Posted: Fri May 12, 2017 5:53 am
by Tom H
Thanks for this. I was here to find out why my new monster box was misbehaving, even after muttering all the appropriate runes over it, this pretty much resolved the issue for me. On another topic, my UAD Apollo Quad Firewire is still falling down pretty regularly with my new setup, my Orion 32 HD arrives tomorrow, we'll see if that works any better.

Re: Windows 10: audio dropouts on multi-core CPU setups

Posted: Fri May 12, 2017 7:45 am
by Rommelaar
Tom H wrote:On another topic, my UAD Apollo Quad Firewire is still falling down pretty regularly with my new setup, my Orion 32 HD arrives tomorrow, we'll see if that works any better.
Didn't Firewire lost support after Windows 7?

Re: Windows 10: audio dropouts on multi-core CPU setups

Posted: Fri May 12, 2017 12:42 pm
by tomtomlog
I have one question when reading this thread, please, someone should tell for what projcts more than 14 cores are needed?
Big sample libraries mostly need much RAM and I don't know how Instruments and effects should be used to have a benefit from so much cpu cores.

I am not joking I really don't know it, CPU power was not really a problem in my projects and if, I can freeze (I am using a normal non overclocked i7) and also DIVA. (Even with 5 Diva instances, effects, other Instruments, sample libs, ... I easily can keep 64 samples latency)

And what I also do not understand, if Cubase uses more than 32 realtime (the limit which MS has setup in Win10) threads for multimedia scheduler then the cpu mostly waits for finishing every thread and the overhead to handle such big amount of threads only waste cpu power.

I do only little programming, but from what I have learned about programming, threads are good, but too much, specially for audio applications have an opposite effect and is more bad for audio performance. So in my opionion, as an non expert, the Limit of 32 is not that bad and I think MS knows pretty well why they setup that Limit.

There's a big difference for graphics rendering (nonrealtime), here it doesn't matter when which thread is ready. There as much threads as possible have an positive effect.

Re: Windows 10: audio dropouts on multi-core CPU setups

Posted: Fri May 12, 2017 7:39 pm
by djw
You want to use your hardware to the full potential. If this causes dropouts that weren't there before, then surely it's not a good idea to put a limit there.