We have found many of our Vbulletin users faced the same problem, there is a significant load average difference when you use VBSEO with your vbulletin forum. We have gone through most of the solution online and found the following suitable with our environment:
As the url suggests, you should put your vbseo htaccess rules in httpd.conf file and change the zend version to ioncube to reduce the load. We have made a solution for our clients on this issue. Go your FTP and create a file called myhttpd.conf and put the following inside of it:
...vBSEO's .htaccess file contents goes here
Once you are done with this, open a ticket in support department of mellowhost with the following information:
Your domain name, Cpanel Username, Server name (If known).
We will do the rest for you.
To change the zend version to ioncube, simply install the ioncube version from vbseo.com
Please note, if your account is suspended with this reason, you have to solve the issue within 24 hours of unsuspention, as vbseo causes high io wait on the server which is not good for the HD health.