We've been running a Magento 1 site for over 7 years and although cpu usage has been quite high, it's not been a concern as performance seemed fine even, it is a high traffic site after all.
Preparing to move over to Magento 2 we installed the latest version (2.3 at the time) and ran it in developer mode along with the M1 site with no hit on server performance.
Now we've finally switched fully to M2 and enabled production mode, wow, cpu usage has gone off the chart https://imgur.com/a/F5w5P7a
I've followed a few suggestions on here regarding enabling caches etc and nothing improves. Thinking M2 would be a much more stable and 'optimised' system, we're not impressed at the moment!
Any suggestions would be very welcome. It's a single server, 16GB ram, 6 Core, Apache/PHP 7.2/MYSQL.