Comment 128 for bug 1801540

(In reply to Marco from comment #87)
> (In reply to Luca from comment #86)
> > I have another info, this is a really odd behaviour.
> >
> > I don't know if you ever used Discord, I discovered this bug because my
> > friends told me my microphone sounded really bad.
> >
> > But another thing I noticed, is that when I enter a voice channel, other
> > than the microphone sounding bad, the Desktop becomes really choppy (GNOME)
> > and video playback on Twitch.tv videos is laggy, it frequently loses
> frames.
> > CPU Usage not even remotely close to 40% on my 6 core AMD CPU.
> >
> > Then, guess what? This DOES NOT happen when using an external USB sound
> > card, which i bought specifically to bypass this bug.
> > Video playback is fine, the desktop is fine and smooth.
> >
> > I don't know what's wrong with this buggy audio driver, but it's really
> > something that needs to be figured out by developers...
> >
> > What the hell how a sound card driver could even mess with the desktop
> > performance? Interrupts?
> >
> > I don't own a bad iGPU, I got an AMD RX 580 with 8GB of VRAM which should
> be
> > perfectly capable to handle the desktop.
> Yea, most likely interrupt stalling if you ask me.
>
> Personally, if the capture is enabled in the integrated audio card while
> discord is enabled, half of the times it begin to randomly loop back the
> audio from the output for no apparent reason (yes, the loop back interface
> is disabled in alsamixer).
>
> I honestly haven’t got system stutter globally, and I basically have almost
> the same hardware as you, Ryzen 2600 + RX580; So I’m not sure as what it can
> trigger that behaviour. I’m using the integrated only to output audio (since
> is much better than my USB external audio card).

I'm on a vanilla Ubuntu LTS install trying to keep things as stable as possible, so no I've enabled no Pulseaudio loopback modules...
In alsa is disabled

With further testing, as long I'm on a discord voice channel with my microphone muted, no stutters at all. The problem begins when the microphone on Discord is recording something.
Of course doesn't happen on my USB audio card