I don't think the 256 would perform better than the 128 would. You have to remember
that the beige has a limited bandwidth pci slot and slow system bus. I just dont think as
fast video card would help it out that much. You may be better off and save money towards a newer mac. Flashing cards isn't always easy and can sometimes get pretty
complicated. Even if you get it right they are not always stable. Its best to stick with Mac
oriented parts.
-maestro