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ISR/DPC lag causing audio crackling, nothing fixes it

Posted: Sun Apr 18, 2021 4:21 pm
by Deimos_F
To be completely honest this is not exactly a Voicemeeter issue. I get this regardless of even having Voicemeeter installed.
But it's been almost one month since I posted my issue asking for help in a bunch of forums (including official Microsoft and Nvidia forums) and I've yet to get helpful feedback (though many replies made it clear I'm not the only one suffering from this issue).

I literally don't know what else to do/who else to ask, and this forum is likely home to some people who might be able to help. So I came here, I hope that's ok.

The issue started about a month ago.

I have very severe audio crackling/popping. The issue is not caused by hardware. I know this because booting in safe mode, booting in normal mode without Nvidia drivers installed, and booting into Ubuntu off of a USB stick makes the issue disappear. I've also tried my audio hardware on a different PC with no problems.

I found out via LatencyMon that I have tremendously high ISR and DPC latencies with DirectX and Nvidia kernel drivers (LatencyMon report at the bottom), and it seems that's the source of the issue.

The main things I have tried are:

- updating the motherboard bios to the latest version
- turning off CPU C-states in the bios settings
- turning off the "High precision event timer" device in Windows device manager (couldn't find any setting for HPET in bios)
- setting the power management in windows to "High performance"
- setting the power management in Nvidia control panel to "maximum performance"
- setting the RAM speed to base values (turning off XMP) (since this didn't work I went back to using XMP)
- turning off Windows "Game Mode"
- turning off Windows "Game DVR"
- removing NVIDIA drivers with DDU (a total video driver removal tool) and installing an older version of the drivers (456.71, from December 2020) (since this didn't work I went back to the latest drivers)
- doing a fresh Windows 10 installation (version 20H2)

Intel Driver and Support Assistant reports there are no missing or outdated drivers on my system.

Since the Nvidia driver rollback didn't solve anything, I've been using the latest drivers. Two Nvidia driver updates and several Windows updates later, the latency is still there and my audio is still crackling all the time.

Nothing fixed the issue. I suspect this might have something to do with the DirectX kernel since that's the one thing I have not been able to individually roll back or change?

All I know is, for a long time I had zero issues and one day for no apparent reason something got messed up, and I have been stuck with crackling audio ever since. I have a nice DAC and headphones, but what's the point if everything sounds like popcorn in a microwave.

I am losing my mind. Please help.

LatencyMon screenshot
LatencyMon text report

My hardware:

i7 8700K (no overclock other than whatever boosting the MoBo might do)
Asus Z370 Prime A
16 GB 2666 Mhz DDR4
2070 Super
BeQuiet Dark Power Pro 750 W
Windows 10 Pro N (64 bit ofc) runs off of an NVMe SSD, I have a few more SATA SSDs but no HDDs on this PC

Re: ISR/DPC lag causing audio crackling, nothing fixes it

Posted: Tue Apr 20, 2021 12:20 pm
by Vincent Burel
well, Voicemeeter is normally not pending on DPC...

if you are not using the last voicemeeter version, we recommend to re-install the last version
following the UPDATE procedure:

if you are using last version, thanks to post screenshot of Voicemeeter and its system settings dialog box.