debug exhausted memory

dear php generalists, I must admit that i have a pretty heave cms. But now a pretty normal query leads to a memory exhausted (at 8MB) crash on the server, but not at home with the same database content. I tried setting the memory_limit even to 0.2 MB (and restarted apache) at home, but still no crash. What is happening? Server is running PHP 4.2.2 safe mode on redhat with a huge configure command, at home PHP 4.3.0 with default settings on windows. I can imagine the 8 MB goes for all PHP processes together. How can I see as a user whether there are more processes going on? Can i see on PHP 4.2.3 how much memory the current process is using? Chris