I think that part of the problem is that the Netscape plugin API only allows the plugin to draw when the browser explicitly allows it to. This is also the case

I think that part of the problem is that the Netscape plugin API only allows the plugin to draw when the browser explicitly allows it to. This is also the case on Windows, but for some reason it's much slower on the Mac. Switching to Core Animation drawing (as in Flash Player 10.1) allows the plugin to draw directly to a backing store in video memory without having to wait for the browser. The plugin still has to request that the view be updated, but it's much faster as it can be done mostly on the GPU. I'm not an expert on plugins or graphics, but that is how I understand it.