I would run DDU to make sure no old drivers exist. Then install the latest driver as well as make sure PX1 is installed. I would also remove any other software you might have used for the old card like Afterburner.

Also it could be worth looking at the power cables and if one cable is using two connections to the card.

I attributed some early black screen flashes on my 3090's to a g-sync bug.  On the bench with GSYNC off and OS optimized - no issues.
 
Have noticed the driver completely restart a few times. Did not research further- I think there is a hotfix for .71
 
but just read that you are aware so that's no help.
 
I pretty much DDU in safe mode every driver install for better or for worse.

Does this occur across multiple systems?

Sajin
Does this occur across multiple systems?

Interesting question. Not sure tho.

And It was a fresh windows install. Didn’t need to DDU. I will try that tomorrow.

transdogmifier
Seems that random black screens, killing of audio and coming back to desktop.... 

I have a very similar issue. I was running a 1080Ti before getting my 3090 and I had no issues with my system. Once i installed the 3090 my screen would go black randomly when I'm watching YouTube, sound would play for a few seconds after screen went black, then would cut out until the screen came back on. I have noticed I can get it to do it constantly when I load up Paint.net app. After a crash since there is never any error, I looked at the reliability monitor and that's where it is showing a hardware crash for memory. Here is a screen grab of what I'm seeing. I know it is not my MOBO or ram, as I've tested both just today. I can run my games without incident, no crashes when playing. 

LazyTonite

transdogmifier
Seems that random black screens, killing of audio and coming back to desktop.... 

I have a very similar issue. I was running a 1080Ti before getting my 3090 and I had no issues with my system. Once i installed the 3090 my screen would go black randomly when I'm watching YouTube, sound would play for a few seconds after screen went black, then would cut out until the screen came back on. I have noticed I can get it to do it constantly when I load up Paint.net app. After a crash since there is never any error, I looked at the reliability monitor and that's where it is showing a hardware crash for memory. Here is a screen grab of what I'm seeing. I know it is not my MOBO or ram, as I've tested both just today. I can run my games without incident, no crashes when playing. 

 
Sounds like my issue, honestly....not sure what the deal is.
 
if I figure it out, I'll tell you
 

aka_STEVE_b
Probably a mix of the latest windows updates and the drivers for new card architecture being buggy from nvidia....

Sound over HDMI had been broken on W10 since the 18xx update until 2004 finally re-fixed it. Something in a subsequent mini-update made it less reliable again.. Not as bad as it was, but not fixed completely. I miss my surround setup as I never had that issue before having to use HDMI sound. 
 
The issue was some sort of driver conflict with nvidia and windows when hdmi came back from standby IIRR.