BD, that's my experience. And I'm finding now that its not just a large amount of frames thing. I can have a single frame movie and if there's a lot of info on screen I get the same slowdowns. It seems CS4 cannot handle any type of normal use without crawling to a near halt. This is including drawing with the pen tool. I think I may be skipping CS4 the same way I skipped MX 2004 when they dropped object level undo (which almost seems to be phasing out again in this version with its new and incomprehensible incompatibilities with IK and the spray brush.

It's true, reviewers shouldn't just talk up new features, they should talk about how the overall software works.