vBulletin Forum Causing High Load or high CPU usage

If you have created your site using a Vbulletin forum and are experiencing high load or CPU issues we recommend you read the vBulletin forums http://www.vbulletin.com. These forums contain numerous bits of advice from others who have similar issues with vBulletin installations.

In particular, we suggest:

1) Disable Search.
2) Enable Persistent Database Connections
3) Turn off any extra stats recorders,

Other specific examples:

http://www.vbulletin.com/forum/showthread.php?t=224462


http://www.vbulletin-faq.com/optimize-vbulletin-server.htm


http://forum.vbulletinsetup.com/f7/optimize-vbulletin-reduce-server-load-2148.html

If you believe your account was hacked:

http://articles.sitepoint.com/asrticle/php-security-blunders/2