PowerBook: Slow Presentations with Video Mirroring (12/94)


I bought a PowerBook 520c for use when making PowerPoint based presentations. We use it to drive an "n-View" LCD display panel.

When a presentation is shown that makes use of any of the "fade and dissolve" type graphics that PowerPoint offers, the PowerBook slows down to an absolute crawl. It will take 5-10 seconds for a slide to change. If you take out these features, it is acceptable, but still is much, much slower than an equivalent desktop model.

Is there a reason for this slowdown?

We are aware of some performance issues regarding PowerBook computers, presentation software, and video mirroring. Video mirroring uses a toolbox routine called CopyBits, which moves information from one part of memory to another.

With complex transitions, the amount of information for CopyBits to process increases dramatically, potentially causing a performance decrease. Simpler transition effects will cause less of a burden on the system.

Customers will also see improved performance when using an external monitor as the primary display, rather than mirroring the PowerBook's display to an external monitor. This is independent of the software being used.

Optimum performance can be achieved by using some of the following suggestions in the creation of the presentations:

* keep color settings to the minimum bit depth actually needed
* reduce use of animation transition effects to a minimum
* minimize use of complicated graphics
* minimize number of individual graphics per slide
* turn off virtual memory during presentations
* disable extensions that are not required during the presentation


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Published Date: Feb 19, 2012