The CPU

This is the first installment of an ongoing series pertaining to computers and their internal components.

The CPU, processor,or Central Processing Unit, has often been referred to as the “brains” of the computer, and that would be true except for the fact that the computer as a whole is essentially like a brain. So what exactly is the CPU then? In a nutshell, it is the component of a computer that carries out the necessary tasks for a computer to run programs and, in general, function as a whole. Using millions or even billions of logic gates(AND, OR, NAND, or NOR) contained in transistors that each pertain to possible choices that could be chosen in a given situation, the CPU receives instructions and performs functions in quite a rapid manner. The process begins when the processor “fetches” an instruction from the RAM(that instruction is part of a larger operation and multiple instructions are given in a sequential manner) in binary(binary is base 2, so it works well with the two-way logic gates mentioned previously) and is placed into an Instruction Register. From there, the instruction is “decoded” and converted into electrical signals, that are then passed to other parts of the CPU to be “executed”. As these instructions are continuously completed, the cache, or short-term memory, of the processor will hold on to certain repeating bits of data that can be used later, further increasing the processor’s speed. Through this fetch-decode-execute process, which happens many times a second, a CPU is able to complete most any instruction given to it.

Modern CPUs have multiple cores, or large groups of transistors that can be used to execute separate functions. The laptop which I am writing this post from, in fact uses a quad-core processor. The greater the number of cores within a processor, the more efficiently tasks can be divided across that processor and the quicker those tasks can be completed. Some CPUs actually have a capability known as hyper-threading, in which every core can simulate the presence of 2 cores, so while my processor has 4 cores, it has hyper-threading, and as such, 8 total cores. Even more speed!

This speed, or clock speed, is measured in hertz(Hz), or the number of instructions that can be completed per second. Most modern processors, in fact, have clock speeds in the gigahertz, or billions of instructions per second. My Intel Core i7-8550U ranges anywhere between 1.8 and 4.0 GHz. Most modern processors also use 64-bit architectures, which, as opposed to the 32-bits of yesteryear, can access double the memory(RAM) and thus complete more tasks at a time. Certain games and programs require a 64-bit processor to be completed. That’s why, for example, there is a version of Windows 10 for both 32-bit and 64-bit processors. Quite a long way from the original Intel 4004, which had a single core and 4 bits of data width. As manufacturers like Apple, Intel, Qualcomm, and AMD continue to cram as many cores and transistors as they can within a smaller and smaller space, CPUs will continue to grow more and more capable, and with that, so will computers and the humans that operate them. With modern Intel i9 and AMD Ryzen Threadripper processors achieving ludicrous levels of performance in ultra-high-end gaming PCs, it’s not too long before these CPUs end up surpassing their creators.

Sources:

https://www.lifewire.com/what-is-a-cpu-2618150

https://www.computerhope.com/jargon/c/cpu.htm

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