I have a Ryzen 5 cpu (6 core, 12 thread) and have just started using Boinc.

Boinc used all the cores so that I could not play a youtube video without stutter.

A related issue is that from the BOINC Manager, the menu item Options, Computing Preferences produces a blank form titled "BOINC - Computing Preferences". I can close the form but not see anything on it.

Just checked and all the versions of BOINC I have both Windows versions and Linux let me put in a percentage of cpus to use when I open computing preferences.

Which version no of boinc are you using? I currently have 7.16.1, 7.15.0 on Linux and 7.14.2 Windows version running under WINE, none of which display the problem. Of course it may be something irrelevant to version number which one of the mods with greater knowledge than mine will pick up on when they see your post.

Thanks for this. Version 7.9.3 (x64).

Options, Computing Settings just gives me a form that's blank except the caption.

I checked the threads using "System Monitor" and they all seem to be "Very Low" priority, so it is not obvious to me why the sound is not getting enough cpu to run properly. I'd try to adjust the number of cores, but can't see anything!

All I can think of is updating to a more recent version of BOINC for whatever platform you are on. I don't recall seeing that behaviour before.

Edit: Faster machine now on 7.16.2 on Linux and the slower one will be too once the pretty colours have stopped scrolling up my terminal.