BAH. It went robotic just now while watching a movie.
 
Seems that it's just a problem with the GPU itself and Dolby Atmos that my 30 series cards just don't have.

 

Nvidia sound driver issue most likely
 
Have you tried? --->Clearing the display cache in windows 11 - it stores many profiles & the sound profiles attached to them. (retains all audio and display settings) (Clear and Reset Display Cache in Windows 11 Tutorial) Now try changing your sound to 16-bit or 24-bit 96000 or higher.
 
Try: disable "audio enhancement" in windows sound settings. Then in Nvidia control panel, in 3D settings changed Power management mode from "normal" to "prefer maximum performance"
 
have you looked at this? Solving Audio Dropouts / DPC Latency Issues With NVIDIA Drivers On Windows 

--> 4k120 + HDR + Atmos ? (known issues @ this resolution)
 

Resplendence Software - LatencyMon: suitability checker for real-time ...

LatencyMon: real-time audio suitability checker - Resplendence
 
 Do the 4000 series card fix Dolby Atmos issues? : r/nvidia - Reddit

What is your actual setup?

using a TV as a monitor / sound - firmware up to date?

Are you using a receiver/ AVR for Atmos? (might help)

using Certified cables?
 
real time security software might also be an issue if it ties up the CPU --> What is Processor Affinity & how to set Processor Affinity on Windows 11

Oh yes, I've been over everything in your list, and much more, for over a year - except the cache clearing, which I'll try today.

My video card is used as an output direct to my Onkyo TX-RZ810 running the latest firmware. DP to HDMI adapter - a nice 8K one that replaced a passive 1080P one. The one HDMI port is direct to the TV. I've tried using the only HDMI port direct to the AVR, but I lose Gsync with the adapter (it doesn't function properly and the screen randomly blanks - I did contact their support to no avail).

I've got a new AVR on order that should be in next week, just to rule it out - a Denon X2800H. I'll even try using EARC on the TV, instead of a direct connection from the GPU. ARC didn't work going from.the GPU to the TV to the Onkyo, and I figured it was an ARC limitation.

In the mean time, Soundkeeper has a brand new version out that I'm going to try with the -All argument to keep all audio, including HDMI, from going to sleep. I don't know if that's going to help, seeing as this happens whilst audio is currently playing... but at this point, I've gone well beyond the obscure with this issue.
 
Edit - no, it just went robotic on me while watching a video (and this was after applying that cache clear reg edit and a restart). Maybe the new AVR will fix this, but I doubt it.

Soundkeeper was going to be my next suggestion
 
Your MB have dedicated audio?  maybe skip the Nvidia sound for a test
 
Sure hope the new AVR finally resolves the issues

Cool GTX
Soundkeeper was going to be my next suggestion
 
Your MB have dedicated audio?  maybe skip the Nvidia sound for a test
 
Sure hope the new AVR finally resolves the issues

The motherboard should have audio... no idea how to make it work with HDMI on the AVR, and it wouldn't have Dolby Atmos. 5.1 works just fine from the 4090, it's what I was using before I started the RMA.

I did retry the -All argument with soundkeeper. I'd originally tried with just the HDMI/SPDIF argument, as well as default. Both of which didn't work. After (cough, properly) adding the -All argument, it may have fixed the drop out / robotic issue. My Samsung S90C doesn't even blank out when turning off the receiver, like it always used to - even with previous TVs, and the 3090s.

If this does work, it'll be amazing...and an outright shame for Nvidia that they allow a 4090's output audio to go to sleep WHILE AUDIO PLAYS!

Does it only happen after the PC has gone to sleep?  If you do a true cold boot does the issue Not happen, unless PC goes into: sleep or hibernate, first? Here you go  use NVCleanstall to reinstall your Nvidia driver  (I've been using this software for a long time, love the ability to limit the Nvidia bloatware & telemetry) Under "Installation Tweaks" select the "Disable Nvidia HD Audio device sleep timer"TECHPOWERUP --->NVCleanstall
Our free software lets you customize the NVIDIA GeForce Driver package by removing components that you don't need (or want). This not only keeps things tidy, but also lowers disk usage and memory footprint.
 
Disable Nvidia HD Audio device sleep timer
 
(edit update image with Red arrow)

 
 
EDIT 4 Clarity ---> the previous screen shot was from techpowerup -- & did not show the Box (I'm talking about) checked .... I just wanted to Show Where to Find it -- replace photo with marked-up photo

 
Ohhh that's interesting (disabling the NVidia sleep timer).
 

Cool GTX
Does it only happen after the PC has gone to sleep?  If you do a true cold boot does the issue Not happen, unless PC goes into: sleep or hibernate, first? Here you go  use NVCleanstall to reinstall your Nvidia driver  (I've been using this software for a long time, love the ability to limit the Nvidia bloatware & telemetry) Under "Installation Tweaks" select the "Disable Nvidia HD Audio device sleep timer"TECHPOWERUP --->NVCleanstall
Our free software lets you customize the NVIDIA GeForce Driver package by removing components that you don't need (or want). This not only keeps things tidy, but also lowers disk usage and memory footprint.
 
Disable Nvidia HD Audio device sleep timer

I haven't used PC sleep or hibernate in... 10 years? I turn that stuff off.
 
What I mean is that I can be watching a video or youtube stream, and while that sound is playing - it will drop out or go robotic. It happens when just watching. It does happen more often when alt tabbing or swapping browser tabs, but even when not doing that it can drop out or go robotic.
 
So far today, using Soundkeeper with the All argument seems to be working... so far. Supposedly it injects a constant stream of zeros that keeps any audio sources from sleeping (but I'm no software engineer - that's just how I interpret it).
 
That Enable Message Signaled Interrupts may or may not be the same thing. I really don't know, but I'll give it a shot while not running Soundkeeper (assuming NVCleaninstall doesn't mess things up (or I manage to mess up the install somehow)).