What is an octa core processor

An octa core processor has eight cores!

You can think of cores like the hands of a person, the more hands you have the more work you can do but at the expense of more energy & complication.


A core is that unit of processor which recieves data and instructions  from RAM (some of these instructions are cached so a core don't have to access RAM again & again which is way more slower )  through memory controller (a digital circuit that communicates with RAM)  and processes and executes these binary instructions.
Every core is independent of other cores so every core has its own execution unit (execution unit has ALU, FPU, cache memory and registers) and control unit.

So, in a way eight core is like having eight discrete (distinct) cpu’s because every core can execute instructions by its own. (this is what done by a cpu.)

{But, because all cores are integrated on the same silicon chip and the bottommost cache is shared and there is only one memory controller and not one memory controller for every core, it (more core) cannot be called a discrete cpu. }

A ‘true’ octa-core processor can handle eight threads of execution  (whether from a single process or multiple processes) or eight process (single threaded) at the same time.

[Note: A process is a container that holds various information about a program e.g. No. of threads of execution ( a process may have multiple threads of execution) and its state, its id, its address, allocated memory etc.]

[Note : If total threads (simultaneous) exceed 8 , e.g. 9, then it (eight core processor) will have to put 1 thread in queue ].

So, if an application is designed to fire eight thread of execution at the same time, then, that task will be over sooner on eight core processor than on a quad core. Accordingly, this can give you more performance.



However, most of the application that is on playstore do not use more than four core simultaneously. Yeah, there are few exceptions like ‘microsoft word’ which ‘can’ use 8 core simultaneously.
Moreover, there is a difference between an octa- core and true octa core. An octa-core cpu cannot use all of its core simultaneously whereas a true octa- core cpu can use all of its core simultaneously. For example- exynos 8895 was a true octa core processor because it could use all of its core simultaneously.  Today, however, all  processors can do this because of software layer 'Global task scheduling'. [ARM implementation of GTS is called big.Little multiprocessing (MP) ]