suPHP is already enabled. Everytime there are different accounts having a high CPU usage php process. So I think it's not a particular account problem.
There is literally hundreds of different possible causes for PHP scripts using high CPU usage numbers and loading the server under your configuration but if I were to take a blind stab at it based on experience with only the information you have provided, I would say that some of your accounts have files or folders configured with 777 permissions and that is likely causing scripts to get stuck as I have seen that problem on many servers and when the permissions are corrected, the load issues often go away.
The following command might help you check for this issue:
Code:
# find /home/*/public_html -perm 777
The following is usually the best permissions for files on
SuPHP based hosting accounts:
755 All Folders (Including ones authors tell you to set 777)
755 All CGI Scripts (.cgi, .pl, .pm, .py, .e)
600 All PHP Scripts
400 PHP Configuration Scripts (configure.php)
*** Basically those you don't want WRITABLE ***
644 Most everything else (Images, Plain HTML, Templates, Etc)
Again you could have some other underlying issue but the above would definitely be the first thing that I would take a look at before looking
next to anything else especially without any other information in hand.
The next item I would look at is how many hosting accounts you have, what the traffic looks like for each of those account, and what are the hardware and resource specifications for your server?
Hope that helps