When trying to load the system status pane on the frontend, the request never complete. I keep bumping up memory and allow execution time for php but either one or the other is reached :

PHP Fatal error: Allowed memory size of 1073741824 bytes exhausted (tried to allocate 32 bytes) in /usr/share/zabbix/include/db.inc.php on line 664

This happens since version 3.x. I tried to troubleshoot a bit myself and it seems that macro resolution takes most of the cpu time, especially the errorMessage() function in CUserMacroParser.php.

Unfortunately, I couldn't find the exact reason for the problem.