Difference between CPU and GPU

While buying your laptop or PC, you must have heard of the terms CPU and GPU and if you're a tech guy, you must be aware of the acronyms of GPU and CPU. GPU stands for Graphics Processing Unit while CPU stands for Central Processing Unit. Before coming to the difference between them, we should first know what are they.

CPU and GPU both are processors which read and execute program instructions. Both contains millions of transistors which alter or manipulate signals as required. Both work on the same instruction sets of Logical Gates.

Birth of GPU

Now, let's go back to the 1999,  this year Nvidia released a special type of single-chip processor into market and Nvidia termed this special processor as Graphics Processing Unit and they named world's very first GPU as 'GeForce 256'. This is where GPU came into the picture.

Point-to-Point COMPARISON 

Cores of CPU and GPU

                   

Source - Mmanss

• CPU is responsible for logical processes, input/ouput (I/O) operations such as Graphic User Interface, printing etc.  while  GPU is responsible for  rendering videos and displaying graphical output on monitor at higher refresh rates.
• A CPU has few cores but powerful for making complex & logical operations, ranging from 1- 61 cores like Xeon Phi has 61- cores which can only execute 61 complex instructions simultaneously during per clock cycle (in a second)  while a GPU has thousands of cores that render thousands of pixels simultaneously during  per clock cycle, and execute a complex 3-D video on your monitor. Like Nvidia GTX 1080 has 2560 shader cores  it can execute 2560 instructions simultaneously during one clock cycle.  In general language , CPU is doing less jobs but complex ones while GPU is doing a hell lot of jobs but dumb ones.  
• A CPU has larger number of instructions sets and it can do anything from adding two numbers to managing all the connected hardware while a GPU can process one kind of repetitive and parallel computing task such as real-time rendering videos and anything which need parallel computing.

• Talking about architecture, CPU has several sub-units such as Arithmetic Logical Unit (ALU), Control Unit (CU), Cache Memory and Dynamic Random Access Memory (DRAM) while a GPU lack ALU, and have of small cache memories and control unit for thousands of cores with a DRAM. 

Architecture of CPU and GPU 
                        

Source -NVIDIA CUDA Programming Guide version 3.0

Conclusion

Both CPU and GPU work on the same principle of process data to make useful information (Logical and graphical both) but GPU is specialized to do parallel and repetitive smalls tasks at higher rates.