title: What makes PHP's mail() function so slow?
body: <p>I made a quick PHP script on my server containing a call to mail() and started testing it. The html page always loads instantly, so I assume that means the PHP containing the call to mail() is finished executing. However, the emails sent from mail() are only ever being received every 10-20 minutes after the call. Why the delay? Does mail() trigger external programs? (the emails are being sent to a gmail email account if that's relevant)</p>