When spamd of CPU usage is high?

When the CPU usage of spamd is high what may be the reason?

> one of the possible reasons for cpu usage to reach 70, 80 or 90% by the spamd process is "sender rate calculation".

> We can set the exim to calculate sender rate (i.e average mails send by every ip per hour) in WHM
-> whm -> Service Configuration -> Exim Configuration Editor -> Add sender rates to the mail log

Enabling this will cause the exim to calculate average mails send for every single message. When there are too many messages, this causes a heavy processing load increasing the spamd usage.

> disabling it in whm and restarting exim will rectify the issue.