If CPU is termed as the brain of a computer, than processor is the main brains of CPU, hence, the name is processor, because it process all the stuff going inside the computer.
A CPU generally consists of Arithmetic Logical Unit (ALU), Floating Point Unit (FPU), registers, L1 and L2 cache memory units. Modern computer processors also have L3 cache memory, and even some processors have L4 cache. "L" here stands for Level.
-ALU is a unit which carries out arithmetic and logical operations on operands in instructions (operands is the quantity on which operation is performed).
-FPU is a unit which manipulates numbers faster than a basic microprocessor circuitury could. It is generally known as math co-processor.
-Register is a unit which holds instructions and other data. It supply operands to the ALU
and stores their results.
-L1, L2, L3 cache memories are very helpful in saving time than in getting data from RAM.
When we purchase a processor, we look for its certain requirements. These are:-
-Clock Speed
-Number of Cores
-Number of Threads
-Cache memory
-TDP (thermal design power)
-Maximum supported memory
So, what are these?
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Clock speed of a processor is the base frequency of a processor. It is a frequency from which we can know that how much amount of data it can go through. Hence, speed of a processor is directly proportional to the base frequency.
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Cores in a processor are the actual physical units which perform calculations or perform tasks. Hence, speed of a processor is directly proportional to the number of cores. Multi core processors are very good in multi-tasking.
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A thread is a single line of commands which is to be processed. Each application has atleast one thread. Now again, core is a physical hardware which works on a thread. Processors with hyperthreading can work faster.
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Cache memory is the memory which is helpful is saving time and energy in getting data from main memory. The cache is a smaller, faster memory which stores copies of the data from frequently used main memory locations.
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Thermal Design Power abbreviated as TDP is a term used for knowing the amount of heat generated by a processor. TDP term is also used for graphics cards in same sense. Knowing TDP is helpful to decide what kind of cooling system is required and how much input power is required.
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Maximum input memory is simply nothing but the maximum amount of RAM installed in the motherboard is supported by the processor or not.
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Going in depth, computer processor contain millions of billions of semiconductor transistors. A transistor is a semiconductor device which have variety of uses. It can be used as a current amplifier, as a switch, etc. As stated, transistors can act as switches, these helps in switching circuits in computers and therefore can act as logic gates. These transistor are similarly used in graphics processors.