Lots of stuttering/crackling in guest sound

When listening to music (e.g. with VLC) or watching Youtube on the guest, there's lots of stuttering and crackling in the sound.


Tested with the following QEMU start commands:

qemu-system-x86_64 -enable-kvm -m 6G -cpu host -smp 3 -cdrom ./linux/kubuntu-20.04-desktop-amd64.iso -boot d -vga virtio -soundhw hda -display sdl,gl=on

qemu-system-x86_64 -enable-kvm -m 6G -cpu host -smp 3 -cdrom ./linux/kubuntu-20.04-desktop-amd64.iso -boot d -vga qxl -soundhw hda -display sdl

qemu-system-x86_64 -enable-kvm -m 6G -cpu host -smp 3 -cdrom ./linux/kubuntu-20.04-desktop-amd64.iso -boot d -vga qxl -soundhw hda -display gtk


If I use the following command (QXL graphics, "remote" access via SPICE over unix socket), stuttering is not completely gone but MUCH less annoying:

qemu-system-x86_64 -enable-kvm -m 6G -cpu host -smp 3 -cdrom ./linux/kubuntu-20.04-desktop-amd64.iso -boot d -soundhw hda -vga qxl -device virtio-serial-pci -device virtserialport,chardev=spicechannel0,name=com.redhat.spice.0 -chardev spicevmc,id=spicechannel0,name=vdagent -spice unix,addr=/tmp/vm_spice.socket,disable-ticketing

and this command for accessing the VM:
remote-viewer spice+unix:///tmp/vm_spice.socket 



Guest: Kubuntu 20.04 64-bit (live), but occurs with many other as well
Host: Arch Linux, with KDE desktop
CPU: Intel Xeon E3-1230v2 (4 cores + hyperthreading)
RAM: 16 GB
GPU: Nvidia GTX 980 Ti