From CSF statistic my server load in 30 days is never higher than 3, I have 8 core cpu and 3 sites with 10 000 unique visits per day. When I reboot my server, and I log in into console, when he is loading cpanel, httpd, mysql etc I check always TOP command and server load is increasing up to 10, then he start to decrease to normal about 0.60. Why server load is high when server is booting? This is not the issue, just the question.
Because when your server starts, all these daemons perform their initialization and health checks. MySQL for instance might check all its tables and apache needs to load and initialize all modules.