A processor is one of the most crucial components of a machine. The processor, also known as the CPU , is the metaphorical brain of the computer. It does all the thinking for the computer. A CPU can have one ormore cores. A core is the part of the processor that does the actual computing. The first thing to consider is the instruction set. This is the language that the processor speaks. The popular instruction sets for use in servers are Sparc , ARM , and x86-64 . Processors using the Sparc instruction set are made by Oracle. While Linux can run on them, the processors are designed to run Solaris, an operating system that is also made by Oracle. ARM is an instruction set that has been around for 30 years and had primarily been used in embedded devices. Cell phones, TVs, and tablets are some of the many places you will find ARM processors.