"GPU, BUT NOT MULTI-PROCESSOR
An unfortunate downside of GPU-accelrated effects such as Cartoon is that they are not compatible with multiprocessor rendering. If you are using one of these effects in your current composition chain, only one processor or core will be used for previews and final renders."
I'm not sure what kind of impact this has Premiere exactly if any but I thought I'd post it. Maybe someone can shed some light on this.
I know the new effects were made using Adobe's PIXELBENDER. Any ideas on how this affects CS4's GPU acceleration?