I have heard too that Win98 can't handle RAM over 256 MB (actually, it has problems with memory over 640 K), and that Win98 is just poor at handling memory in general. Specifically, though Windows is supposed to be a multi-tasking environment, Win98 is awful at multi-tasking and leaks memory all the time.

I use Win98 with 384 MB, and I don't have too many lock up problems any more. Suggestions:

If your renders are big enough to use the swap file (mine are usually simple and don't need the swap file), make sure the drive on which your swap file exists has plenty of room. Win98 defaults to using drive C:, even if that is not the best drive to handle your virtual memory. You should custom-set your virtual memory settings. Ironically, when you try, you get several warning screens to the effect of "changing Windows settings could destroy your computer and the world," even though setting the settings yourself usually takes care of a lot of crash problems.

Never have any other program running while you're doing renders. Never.

While this may be more supersition than anything else, since I have no hard evidence to confirm its effectiveness, I think Win98 needs to have its memory occasionally "cleaned out" by closing down all programs periodically and starting them again. It seems that Win98 has trouble releasing memroy that it is no longer using. I think shutting down and restarting every now and then helps me.