there are many difference between i7 and i5 intel processors.
Even i5 have classified into many types based on socket and cache memory.
i7 has got extreme features such as hyper threading,turbo technology,and type of memory mode available in i7 is triple whereas it is dual in case of intel i5.
Turbo boost technology is available in some models of i5.
But there is no turbo boost in intel i3 which is the lower version of i5.