Weird WPF 3D rendering artifacts (see Youtube video)

Question

When I'm rendering 3D graphics I sometimes get weird rendering artifacts, especially if my PC is heavily loaded.

http://www.youtube.com/watch?v=LN15D_s2_98

I'm still trying to characterize what sort of 'loading' matters the most -  RAM and CPU alone don't seem to do it -  it seems to be video-card bandwidth -  if I'm running an app such as a video display, capture or editing program that's when it seems to happen.

Microsoft has a KB article -  http://support.microsoft.com/kb/963021  advising to upgrade video cards or drivers - but I'm not sure what good it is because we don't write these apps for ourselves -  we write them for customers and clients where we have no control over what video hardware or drivers they have.

My question is how do we prevent artifacts like these on the client's PC?