Please provide the environment detail, AR Server version, application version , OS, DB etc
Look at this thread for performance improvement if you are on ver 9.xBMC Certified recommendations for customers adopting 9.x
This is going to sound obvious...but, the CPU is high because the process is 'doing' stuff. The best way to find out what it's doing is turn on API/SQL logging for a bit (half an hour?) and then analyze the logs to determine where most of the activity is coming from, what user, what process, etc, and then analyze from there to see why that activity is happening....
What are the operations which are happening on this? (I mean operation Ranks)
Is user connection is also landing on this Server?
You May need to check java heap stuffs?- https://docs.bmc.com/docs/brid91/en/bmc-remedy-ar-system-9-1-application-server-performance-benchmark-configuration-settings-610402394.html