Introduction
If using an external spam service and do not want the overhead on the cPanel server the spamd service can be completely turned off.
Procedure
Access WHM and access Tweak Settings and then set "Enable Apache SpamAssassin™ spam filter" to off.
Then also be sure it is disabled in WHM under Service Manager. This is done by unchecking the enabled column for "Apache SpamAssassin™" and then clicking save.