People frequently refer to the CPU as the “brain” of the computer. This analogy is poor as the human brain both stores and processes data, while the CPU only processes data (the temporary storage of the data about to be processed/has just been processed is handled by the RAM).
The CPU together with the RAM takes care of the processing function of the computer. Both are volatile, meaning they rely on being supplied with power to retain data.
The CPU is a chip — that is to say a small, integrated circuit board — that is plugged or slotted into the motherboard. The bottom side of the CPU has fine, metal pins that “plug” into the motherboard. The pins are easily bent or damaged so great care must be taken to slot the CPU into a ZIF socket.
Because the CPU generates a lot of heat it almost always has a heat-sync with a fan mounted on top of it. The heat-sync is glued onto the CPU; this glue eventually deteriorates to the point that the heat sync comes loose from the CPU and must be reaffixed.
Once CPU can contain multiple cores. Simply put, a dual core processor has 2 cores, in theory doubling the speed at which it can process instructions as each core can handle an instruction at the same time (in practice the increase in speed is not this great).
We want our CPU’s to be fast! The faster a CPU the more instructions it can carry out per second. We express these cycles in hertz (or multiples thereof), for example, 3.6 GHz (gigahertz).
To overcome the lag caused by data that is processed, sent to RAM, only to be processed again, modern CPU’s now include cache memory. This is a small amount of memory physically included in the CPU. Like all caches, it’s objective is to speed things up. Modern CPU’s have multiple caches.
This is a complex concept and all you really need to know is that you will see that modern CPU’s found in PC’s and laptops generally have 32-bit or 64-bit architecture.
You should know the names of the leading manufacturers (and even follow news of the developments taking place as they battle each other to create smaller, faster chips). Two of the leading manufacturers are Intel & AMD.