We are experiencing very high CPU usage in magento. The Process are listed as php. If a single user visit the website homepage CPU spikes to 30-40%. We tried fresh magento installation with nothing in the database but it still does the same.
We have PHP 5 with PHP 5 Handler Suphp. We are on dedicated server with remote mysql.
Is it normal?
Steve
Edited
I have now switched to Nginx and noticed that the website is super fast and the CPU usage is down to 1/4 of what it used to be with Apache.
Now working to install Varnish for even better speed. My recommendation for everyone out there is to move to Nginx without wasting time.
Magento can be very intensive, it would depend on the specs of your server on how much strain you would get as a percentage.
Once you enable caching, and add in something like APC / EAccelerator it should drop a bit though.
A Good solution would be to scrap SuPHP and Apache and use Nginx as your webserver, this will greatly reduce the memory footprint and CPU load on your server.
Alternatively you can look into adding Varnish or Squid caching proxies which would also reduce CPU load by quite a bit.