You Guys are Awesome..!!! Lets get to the topic.


So most of us assume that Core i7 is better than Core i5 and well Core i5 is better than Core i3. 




Answer is a BIG No and You may ask me why?

The answer is simple; The number associate with Core i3, Core i5, Core i7 are representing its processing powers only. 

So Core i7 has no 7 core, i5 has no 5 cores and i3 has no 3 cores.

To understand this we need to know what Core and Hyper Threading is, how they are related and a little bit of math around it.

We are taking Core and Hyper Threading together as they are related.

A processor i3, i5, i7 or old intel processor like P4 etc. may have one or more core built in it.

One task or one thread can be executed by one core at a given time.
However, Hyper Threading technology allows single core to perform 2 threads simultaneously.

Single core without hyper threading = 1 Task or 1 Thread
Single core with Hyper Threading = 2 Tasks or 2 Threads simultaneously

Dual core without Hyper Threading = 2 Task or 2 threads simultaneously.
Dual core with Hyper Threading = 4 Task or 4 threads simultaneously.

Now,
All i3s has only 2 cores
All i5s has only* 4 cores.

All i3s has hyper threading
All i5s has no* hyper Threading (here is the catch)

So,
i3 =  2 core + Hyper threading        = 2 X 2 = 4 threads, its represented as 2/4
i5 =  4 core (no Hyper Threading)  = 4 threads , its represented as 4/4

Thus,
i3 and i5 stand together as they both will finally deliver 4 threads simultaneously

Whereas i7 has "Core/Thread" available in range 4/8, 6/12 and 8/16

Well there are other factors like Cache, Turbo Boost etc which we need to consider before embarking which processor is best per our requirement. However from pure Core and Hyper Threading i3 and i5 stand together.

Disclaimer * :  3 out of more than 37 i5 has 2 core with hyper threading, But finally they delivers only 4 threads.