because it is multi-thread. There are only two cores cpus but mutithreaded, therefore it will be shown as 4 cpus.

i3,i5 first gen= 2 core

i3 2nd and 3rd gen=2 core

i5 2nd and 3rd gen= 4core

i7 =4 cores

See more in wiki

http://en.wikipedia.org/wiki/Intel_Core

http://en.wikipedia.org/wiki/Hyper-threading

A simple google query would have lead you to the correct answer. It is a dual core processor that offers hyperthreading to handle 4 threads at once.

Go to intel.ark.com to find the details of any intel processor

http://en.wikipedia.org/wiki/Intel_Core

As it was well said, i3 cpu is a dual core chip. The monitor shows 4 cpus just because each core can support two separate threads. The difference from an actual 4 cores chip appears in the management of cache memories, which are shared among threads.

It is a dual core processor with hyper-threading technology. It only has 2 physical cores but it is comprised by 4 logical cores.