Hi Kevin,
I responded to your ticket with some clarifications earlier today. The load you're seeing in the VPS is caused by the processes running right inside the VPS, in your case load appears to be caused by exim/assp.pl processes and (most important) by the MySQL queries that involve data copying into the temporary table - just run a google search for "Copying to tmp table" to get a rough idea of what such non-optimized queries can do to your overall performance.
Please follow up through the ticket if you require any additional assistance regarding what was discussed there.
Regards,
Paul