The CPU, or processor (central processing unit), is one of the most critical components of a server. It is responsible for handling all processing tasks, and delegating requests for resources between RAM, storage devices, and other parts of the system.
The performance of a dedicated server is often directly related to the power of the CPU it is equipped with, although other factors such as storage configuration can also play a significant role. In general, processors with a greater number of cores, and greater frequeny per core (usually measured in GHz), will provide increased performance for all tasks that require processing.
[From the RedArray Knowledgebase: https://www.redarray.net/portal/knowledgebase/22/What-is-CPU-processor-and-how-does-it-affect-a-dedicated-server.html]