(Not sure if this should be under sound, video, or both, but here goes...)
Just installed mageia 2 in VirtualBox 4.1 hosted on CentOS 6.2. I keep VB up-to-date as soon as updates come out, and that includes guest additions (4.1.18 as of today). When I play a flash from a web page using Firefox in the Mageia guest, it sounds a bit choppy and the playback seems to be a bit fast. I don't have this problem on the host or other guests on the same system. I've tried the Alsa and Pulse audio alternatives, and I have not done any additional mods to the default installation of Mageia 2.
Let me know what info to provide if needed. I note that others here have posted reasonably good results with Mageia 2 running as a VirtualBox guest.