core i7 and core i5 comparison

Should I choose Intel Core i9, Core i7 or Core i5 CPU?
intel and amd have returned in a new battle of microprocessors, with intel launching a new product line, called core i9. this is the fastest desktop processor ever.
Does your computer need Intel Core i3, i5 or i7?
intel has a rather confusing way of naming microprocessors and the most frequently asked questions are: what is the difference between the i3, i5 or i7 processors? which one should i buy for a computer?