CPU usage itself isn't necessarily a bad thing. Are you facing any actual performance issues (e.g. slow loading websites), or are you just trying to improve the usage numbers?
1. I used VPS Server, cPanel self "Default" did hit CPU higher. I've checked from apache configuration.
Before cPanel default - apache configuration.
Minimum Spare Servers: 5
Maximum Spare Servers: 10
Server Limit (Maximum: 20,000): 256
Max Request Workers: 150
Max Connections Per Child: 10000
Keep-Alive Timeout: 5
After. I've tried to stop higher on CPU, our server. It's not my.cnf, It is Apache configuration issue with VPS Server. But there is no for DDoS Attack, I was checked IP connecting our VPS they do not DDoS attack as well, smallest of connection IPv4. VPS was fine few days ago. I've seen a bit CPU high more than 3.00 a few seconds to 1.5, 0.30, 0.01 in Load Averages.
Minimum Spare Servers: 25
Maximum Spare Servers: 20
Server Limit (Maximum: 20,000): 1024
Max Request Workers: 1024 <--------- 150 limit is bad to hits CPU Higher more than 35.00 Load Averages. I saw it in before own my eyes...
Max Connections Per Child: 0
Keep-Alive Timeout: 100
VPS has a little hit CPU 1.55 or 3.00 Load Average has no issue been in 2 days for now. What I said wanted to stop CPU higher from Apache configuration. Also, I enabled "Memory Usage Restrictions" 2499" MB has been enabled. MB = 2,499GB. Isn't it good? I have a 30GB RAM our VPS as well and an SSHD.
I guess, These settings recommended by liquidweb knowledge. I followed it. But that is not my VPS host, It's another server.
But for now. Has no issue three or two days. I'm not sure. If that was settings good or bad.
2. Now a few minutes ago, I've seen Pure-SFTP hits CPU has 9.09 0.02 /usr/local/cpanel/bin/pureauth. It's strange isn't? But not load average, It was CPU%.