This didn't resort in a 504 but was a situation I can replicate over and over with the server on 0.4 load averages: xxx.xxx.xxx.xxx - - [07/Sep/2008:17:16:54 -0500] POST /forums/private.php?do=insertpm&pmid=101373 HTTP/1.1 upstream_response_time 37.832 msec 1220825814.697 request_time 37.833