I'm currently having my Tibook 400 upgraded by Daystar to 550mhz. The expense is worth it because most of the components on my computer are new and I accidently cracked the plastic side of the case near where you plug in speakers/earphones, causing a stress fracture near the hinge (which will turn ugly soon.) So they are putting on a new top case and airport card all at the same time. I have a gig of ram in it and have no intention of giving it up soon. Just thought of mentioning the idea of upgrading your Tibook. It may seem an unjustified expense for some, but I am now so used to the keyboard and have heard so many complaints about newer Apple laptop keyboards that I just don't want to part with this GREAT machine.
Sorry no help on the video question except an upgrade might make it run better.