*effected* ? I think you meant *affected*:)
My guess is that the more complex the model design, the longer it takes to redraw each frame. One thing you can do to rectify that is to d/load Metasequoia and redraw them yourself with less complexity. A look at the Metasequoia intro page will explain it all far better than I can.
Alternatively, you can use a lower resolution or get a faster computer ...
RR