Audio playback in host massively stutters whenever a VM is running

[zazz]

After upgrading to VirtualBox 5.1.2 (from 5.0.…) it started happening — audio playback in host massively stutters whenever a VM is running and it happens very frequently and sometimes doesn't stop until I power off the VM (even pausing VM has no effect). Stuttering ends in the exactly same moment when VM finishes shutting down.
In 5.0, there were no such problems.

Problem occurs with a guest OS being windows xp 32-bit, but I guess it will be the same with all guests.
Guest additions and extension pack are also updated to matching versions.
I tried lowering CPU execution cap in VM settings and it didn't help. Disabling audio in VM settings also didn't help.

More details about host:
Host OS is OS X 10.11.6,
I'm playing audio in foobar2000 via wine (1.9.10),
the audio output device is a digital interface (optical cable),
I also have Soundflower installed.

Everything worked OK before (VirtualBox 5.0 didn't cause such problems).

[socratis]

Host OS is OS X 10.11.6,
I'm playing audio in foobar2000 via wine (1.9.10),
the audio output device is a digital interface (optical cable),
I also have Soundflower installed.

It would be kind of/rather difficult to replicate your setup. Any chances of simplifying it to the bare minimum where the problem occurs?

[zazz]

It would be kind of/rather difficult to replicate your setup. Any chances of simplifying it to the bare minimum where the problem occurs?

There are some chances, but I don't have time to do it right now.

[socratis]

Just to let you know there have been several reports about problems with sound in 5.1.2 on OSX hosts (see Sound doesn't work on VB 5.1.2). You must be one of the few ones that still has working sound.

Unfortunately you didn't mention your guest OS or the sound card emulation that you're using. But try to downgrade to 5.1.0 and see if it changes the situation.

[michaln]

Actually I think the complaints about *host* playing back audio stuttering when a VM is running (not VM playing sound). But it's all a bit vague.

[socratis]

You, sir, seem to be absolutely correct! I re-read the thread and it definitely sounds like host problems while a VM is running. That changes the viewpoint completely. I'll shoot in the dark and say host resource shortage.