High CPU time

NT server 4.0 sp5 dual PIII 500 processors 512MB RAM and two hard drives (8G and 60G) both drives got plenty of room to grow.

Exchange Server 5.5/sp3 and MicroTrend virus scan application.

I have been monitored the Exchange Health for the past three weeks. Noticed that the both system idle Process (CPU time 45-75% ) and Processor (ave 17600 min Interrupts/sec ) were high.

For the Processor Time in DSAMAIN, EMSMTA, STORE, MAD,and etc were doing normal.

Any suggestions? I will appreciate… 🙂

Thank you