Hello,
I experience very strange situation with my xVM VirtualBox 1.6.2. and OpenSUSE guest machine. My configuration is:
Guest machine: OpenSUSE 11
Guest additions: Yes
Symptoms: If the audio of the virtual machine is enabled, the guest takes 100% CPU load. This only appears on a OpenSUSE and Mandriva GNU/Linux distributions.
The host operating system is Fedora 10 with ALSA compatible sound card.