I have the same situation like the forum thread http://community.apachefriends.org/f/viewtopic.php?f=16&t=41052&p=162217&hilit=Mercury+memory+leak#p162217
My mercury process memory look normal. But global memory is become very big after one night.
When I restart mercury service , the global memory is become small.
Please look grab pictures in Google Picture Album: http://picasaweb.google.com/100932786916629098871/XAMPPBug?feat=directlink
OS: Windows XP SP3
XAMPP: 1.7.3
Mercury/32: 4.7
Mercury protocal modules: SMTP server (only use this)