I have been struggling lately with constant audio dropouts on our main Windows PC (a monster machine running Windows 11 with a 12th gen Intel core i9 CPU and an NVIDIA GeForce RTX video card – also used for video editing).
A true nightmare making any real time audio performance impossible on this machine for weeks!
It took some time to figure it out, but here is a trick that may help you solve such audio dropouts, even when DPC latency issues with faulty drivers cannot be solved!
To learn more about DPC latency, you may want to read our Windows PC Optimization article.
By the way DPC stands for Deferred Procedure Calls (Wikipedia definition).
NVIDIA Driver DPC Latency Problem
After applying the same optimization tricks as for all our audio laptops (yes it works for desktop PCs too, even though it is usually not necessary), audio performance was still very poor, even with rather large buffer settings.
CPU usage was not the problem though, as the CPU meter in our standalone applications was really quiet:
So of course, the first thing that comes to mind in this case is DPC latency issues… An the culprit indeed seems to be the NVIDIA video driver, as shown by the Latency Mon report below:
Almost 4ms of DPC latency is huge, and it means dropping audio buffers every time this delay happens! If interrupts from other drivers take too much time to execute, they may indeed prevent the audio driver from doing its work in time, as explained with more details in our Windows PC Optimization article.
After further investigation on the Internet, this issue has been happening to many people lately, and it may have been caused by the combination of recent Windows updates and issues with NVIDIA drivers, which of course you cannot disable!
Anyway, after trying every possible tweak described in this forum thread, one trick finally solved the problem, and I guess it may be applicable to other cases when DPC latency keeps being an issue for audio dropouts, and the faulty driver cannot be disabled.
The Trick
The idea is to force the audio driver and the driver causing DPC latency issues to work on different CPU cores, so that the audio driver is not blocked by the faulty driver that takes time to execute.
To do that, you can edit the interrupt affinity setting for the drivers. You can either go thru the Windows registry manually (good luck!) or use the Microsoft Interrupt-Affinity tool:
In this particular case, the GeForce driver’s affinity has been set to Core #4, while the audio driver has been set to core #16.
Warning: the NVIDIA driver resets this affinity property when updated (and sometimes when rebooting), so you might have to do this again from time to time. The Interrupt Affinity tool also seems to throw odd errors from time to time while editing the registry for this particular driver, but it does not seem to affect the result.
The Result
It works! No more dropouts, even at extremely low latencies and high CPU usage!
The DPC latency issue with the NVIDIA driver remains, BUT it is now not a problem anymore for the audio driver that can do its work (on CPU #16) while the other CPU core (#4) is busy working for the graphics card (nvlddmkm.sys driver), as you an see on the Latency Mon utility screenshot below:
I guess this is applicable to any other driver that may cause such DPC latency issues and that cannot be disabled (it has to respect the core affinity settings though – some drivers may override the behavior and not take the affinity into account). So if you have a laptop that has never been capable of real time audio due to DPC latency issues, you may to to try this out!
Back to music now… Enjoy, and feel free to report your successes of failures with this trick!
Thanks for this! I m experiencing this issue top and I’ll try your tips! Just one question can you be more specific in commands to use while using interrupt affinity tool? I mean how to assign different drivers to a different core in case of ASIO drivers and Nvidia drivers! Thanks in advance and have a Great day
Experiment with the Interrupt-Affinity tool to set the best result for your specific computer.
That’s just crazy! Why normal people have to deal with this!
Thanks for sharing!
That’s definitely a good question! 🙂
Great article, I was struggling with this as well.
Glad to help!
Of you have no single clue what you are mumbling about, maybe leave posting it on internet for somebody else. 4 second dpc latency would cause you unusable processing times not even talking about ANYTHING realtime. By selecting GPU interrupt filter policy spread out to all CPUs will cause more problems than fix cause of uneven load through cores from other processes, different proximity to memory controller etc. Etc. Who the hell buys 3080 for realtime audio applications anyway??? Best to just use integrated graphics or just uninstall the GPU or driver, you can also find low latency driver if you really need it. Wouldn’t trust you plugging a monitor into a wall socket though, stay away from toys for big boys.
Well, you may want to read the article once again. That’s 4 milliseconds, not seconds, or the computer would indeed be unusable for anything :-). Here the GPU is actually assigned to a single core, not spread onto all cores, so that it is working on its own dedicated core and does not interrupt real time tasks. You may want to use a computer with a decent GPU for real time audio for many reasons. Here the workstation is used to do both video and audio, so that’s needed. And it runs very well now.
Just set interrupt filter to CPU closest to memory controller and the one that is free, also you can limit cycles with MSI mode tool to 1 to reduce CPU time to minimum and adjust priority to your liking
Thanks for the tip. We are not talking about multiple CPUs here but a single multicore CPU, so maybe I am misunderstanding, but I don’t think this is relevant.
Great article, however when I try to do this on a new Asus G16, it does not save the states, telling me the registry will not allow it. I’ve tried multiple times with both the x64 and x86 version of the tool.
I disabled hyper threading first, I am guessing that there is some kind of security measure in place? Do you know any way of getting around this?
Did you run the tool as an administrator? Also if you close and then re-open the tool, are the settings really reset? I remember seeing a couple of error messages but when re-opening the app you could see that the settings were actually saved.
Hello,
You can also chose to force nVidia driver to low latency mode which worked for me:
=> launch nVidia control panel
=> chose to set it for all in Global tab or for your DAW in Program tab
=> select “low latency mode” and set it to “ultra”
=> apply and close, that’s it!
Hope it helps…
Thanks for the heads up! Is this a new option in the driver? I don’t remember seeing this setting in the past.
I don’t know really. I discovered that when I tried to understand why my brand new big powered PC had a worse latency than my old one! There is also another tuning I then discovered in the nVidia driver, it’s about power limitation of the GPU which can sometimes had very bad effects on latency….
SOLVED for a similar configuration:
Operating system Windows 10, recently installed on a motherboard ASRock P67 Pro3 (bought and used since 2011), coupled with an Nvidia GTX 1660 graphic card, and Envy24 as audio controller.
=> DCP_violation were happening each time some video (with sound) was played, which did not happen on my Windows 8.1 OS.
What didn’t work:
updating the drivers, modifying some option from Nvidia control panel.
Only when I divided the audio/graphic works between my multicores CPU (Intel i7 2600K), with the help of the Microsoft Interrupt-Affinity tool, was the problem finally solved 😀
Thanks a lot, guys !
… But man, I wonder what is the terrific change which happened in Windows 10 OS and the NVidia driver, that could lead to such a problem… I was not too far to consider buying another motherboard if it didn’t work ;(
Yes that’s indeed a crazy situation! Glad that the article helped!
Wow, I was just about to do a complete reset of my system. Massive audio dropouts, and the culprit was nvidia driver. Not about to remove my GPU!
I’ve been optimising PCs re audio for so many years but had never heard of this solution. Thanks so much for making this guide.
Glas that it helped! This method is indeed quite efficient but not very well documented!