The busiest time is around this part of the day, and the CPU is stick at 50%.
Sometimes it goes to 100%
Is this because of the RAM?
Or is it due to some script straining the server?
could be either one, or anything, cant do anything here but guess, surely you didnt expect someone to be able to tell you just on the info you gave , anyway you can check in whm > CPU/Memory/MySQL Usage or check out top while its happening.
I recently went to that configserver firewall and security, it will also tell you when cpu usage is real high or a certain process is hogging resources