Run htop command from the Linux console to determine the problems. With this command, you can easily find out if your system is overloaded for reasons of insufficient CPU performance, small RAM, or whether processes wait too long for I/O operations with the system being paralysed by slow hard disk.

• Insufficient RAM amount

Problem	Too small RAM is installed, hence swapping to hard disk which decreases server performance.
Solution	Add RAM to server.

• Slow hard drive

Problem	In htop, you can see high values in load system section, yet graphs show sufficient free RAM and CPU cores are not loaded at 100% - most likely it is a problem with insufficient write/read speed from system hard disk.
Solution	Replace hard disk with SAS/SSD.

• Small CPU performance

Problem	The processor cannot deal with common tasks and keeps running at 100%.
Solution	Buy more powerful server.