373Mb is pretty big for a couple of Poser figures... I seem to remember from one of the Bryce manuals that you can get away with a file up to half the size of your RAM, but any bigger than that and things get a bit problematical. I've got files with six or seven Poser figures in that are only just over 100Mb, but they are all P4 or V2/M2 figures. If you want to use a lot of the top-end figures, a Gb of memory would probably be of help to you. I would second the advice above to delete any mesh that's hidden under clothes or behind other objects, and stick your background figures on 2D planes. It saves a lot of memory. Cutting down of the specularity settings may speed up your renders a bit, and if things are slow even in the wireframe view, like when you try to move something, lower your wireframe resolution; this helps a lot. I don't know whether you're fairly new to Bryce, but unfortunately it is quite slow, and if you are doing complicated renders you may just have to be patient. The good-quality Poser hair does take a long time to render, and running other applications alongside Bryce can be slow -it can take me up to 30 seconds to open an image with ACDSee when Bryce is running, and I have 3GHz and a Gb of RAM. Also running other stuff against Bryce will slow your renders down unless Bryce has priority.