understanding memory allocation

Hi all, Does anyone understand the difference between memory_get_usage and memory_get_peak_usage with and without the parameter? I don't understand how the allocations could be so far apart. eg (small script that takes a minute to run): $ php -f file.php

Peak usage (true):       4,608.00000
Peak usage (false):      8,040.87891

The number is just memory_get_peak_usage($param)/1024 with $param true/false. Which one is right? How do I tell? Thanks. -- Postgresql & php tutorials http://www.designmagick.com/