Windows9x has issues with large amount of RAM. It wasn't designed to handle huge amounts of RAM because when it was designed RAM was expensive and even 128MBs was considered a lot. Search MS' website for 512k and you will find several tech articles about it...512 is basically Win9x's "limit" so you're right there.

Basically, Win98 has finite resources, and what it does is gobble those resources up for things like the Disc Cache (the one that keeps track of what files and folders have been accessed recently so the next time they are accessed Windows can do it faster). That's why you can render several times, then Poser suddenly starts to freeze...as you worked, Windows sapped away all your resources until there weren't enough left for Poser to do its thing.

By altering your Disc cache settings you restrict Windows from being greedy and taking more resources than it needs. If you aren't comfortable editing your registry, you can get Cacheman from CNET and other download sites to tweak it (and other settings) for you. I don't let Windows take more than 64k of RAM for the disc cache. You can even get away with less...try different settings and see what works for you. Note that too low of a setting will make Windows go slow (has to seek out more files and folders more often) so don't go crazy.

In any event, note that this is not a fix all. High res textures require a lot of active memory. If you use a lot of high res textures and hi res characters like Vicki in one scene, Poser may still freeze up. Having reduced file sizes available is a good idea for those times. Win2000 and XP handle memory better and don't have as many issues with this, so you can always consider changing to one of those.

BTW: Poser is the only program I have that freezes up like this...I don't think it currently does that great of a job of allocating things either :(