What is a Processor? 

The processor is an electrical component that perform an operation on external data, usually for memory or for some other data Unit/Stream.(In easy words it determines how fast instruction to an device can be executed.) The performance of a computer is determined by three key factors :- i)Instruction count, ii)Clock Cycle per Instruction(CPI), iii)Clock Cycle Time this whole unit is called a processor.  It is usually built as a microprocessor on a single metal–oxide–semiconductor integrated circuit chip. The Processor is also called as Central Processor Unit (CPU).It is the active part of the computer or Mobile devices, which contains the data path and control and which adds numbers, tests numbers, signals Input/output devices to active, and so on. A Mobile CPU/Processor are designed in such a way that it remains cool enough without the fan. Mobile Processor uses lower voltage than Desktop that reduces the unit consumption of electricity. A mobile Processor can work on different power levels. Under the low processor loads the clock frequency of processor may fall down and that increases the Battery Life.

History

The Multiple individual vacuum tubes, numerous individual transistors, or multiple integrated circuits were used to build CPUs in the past. The below table shows growth of the Processors/CPUs.

Year

Technology used in computers

Relative Performance/Unit cost

1951

Vacuum Tube

1

1965

Transistor

35

1975

Integrated circuit

900

1951

Very large-scale integrated circuit

2,400,000

1951

Ultra-large-scale integrated circuit

250,000,000,000


*Integrated circuits are used widely now a days.

Processor's Architecture

The Architecture of a Processor's is very important as it effect's directly the performance of the any device. It is the balance and composition of the cores into the multi-core architecture. Multiprocessor consists of eight scalar processor (SP) cores each with a large multithreaded register file (RF), two special function units (SFUs), a multithreaded instruction unit, an instruction cache, a read-only constant cache, and a shared memory.

Processor Design

As you known Processor is a key component of computer hardware. The Design process includes selecting an set of instruction and a certain type of executional prototype at results into a microarchitecture. The working of any processor is to implementation of list of instructions.
As in today era the size of smart phone are compacted so the architecture of processor must be minute and faster.

Why use a multiprocessor, rather than several independent processors?

The parallelism within each multiprocessor provides localized high performance and
supports extensive multithreading for the fine-grained parallel programming models. The individual threads of a thread block execute together within a multiprocessor to share data. The multithreaded multiprocessor design we describe here has eight scalar processor cores in a tightly coupled architecture, and executes up to 512 threads. For area and power efficiency, the multiprocessor shares large complex units among the eight processor cores, including the instruction cache, the multithreaded instruction unit, and the shared memory RAM.

CORE

The Processor are imposed on integrated circuit(IC) microprocessors, such one or more processors together on a single IC chip form's a core. When there is more than one processor it is known as Multi Core. With Dual processor it is called Dual Core, Four processors is Quad Core, Eight processors is Octa Core. Now further to increase the speed of Processors the threads was introduced. The threads is a further divided part within the core. 
The different type cores in the Mobile Processors till now are :-
1) Dual Core
2) Quad Core
4) Hexa Core
3) Octa Core

Company that Build's Processors

ARM Architecture
Hisilicon
Samsung Exynos
MediaTek
Qualcomm Snapdragon

Company that Build's Desktop & Laptop's Processors

Intel
AMD Processors

GPU

The GPU stands for Graphical Processing Unit. It was invented to accelerate graphics they are becoming programming platforms in their own rights. GPUs depends on parallelism action. The GPU generates 2D and 3D graphics, Images, and Video that enables Windows,IOS,Android or any other OS(Operation System), The modern GPU that we describe here is highly parallel highly multithreaded multiprocessor optimized for visual computing. To provide real-time visual interaction with computed object via graphics, images, and video, the GPU  has a unified graphics and computing architecture that servers as both a programmable graphics and computing and a scalable parallel computing platform. PCs, game consoles, and some mobiles uses in combine combination of GPU with a CPU to form heterogeneous system.

GPUs and their associated drivers implement the OpenGL and DirectX
models of graphics processing. OpenGL is an open standard for 3D graphics
programming available for most computers. DirectX is a series of Microsoft
multimedia programming interfaces, including Direct3D for 3D graphics. Since
these application programming interfaces (APIs) have well-defined behavior,
it is possible to build effective hardware acceleration of the graphics processing
functions defined by the APIs. This is one of the reasons (in addition to increasing
device density) why new GPUs are being developed every 12 to 18 months that
double the performance of the previous generation on existing applications.
Frequent doubling of GPU performance enables new applications that were
not previously possible. The intersection of graphics processing and parallel
computing invites a new paradigm for graphics, known as visual computing. It
replaces large sections of the traditional sequential hardware graphics pipeline
model with programmable elements for geometry, vertex, and pixel programs.
Visual computing in a modern GPU combines graphics processing and parallel
computing in novel ways that permit new graphics algorithms to be implemented,
and opens the door to entirely new parallel processing applications on pervasive
high-performance GPUs.