Hey Patrick, what makes you think that? I've done a few simple tests, nothing very scientific, but it seems that around 90-100 MB seems to be the limit for a single process. If you have multiple users and multiple processes, I have no idea what the total would be.
It would be cool if the resource limits were flexible based on server load though. I have a report generation function that I've rewritten several times to keep it from getting killed. It may run up to once a week, for around 20 seconds or so, but because I have to limit the memory to around 60-70MB, it runs up to 120 seconds. It's a shame because the amount of time I've spent rewriting the process just for such rare usage is really a waste. Flexible limits would be great!