The Haswell has voltage regs on the die itself, Ivy does not, I read about ~10% performance increase. Different socket of course, I also read it does not OC too well for heat reasons I gather, roll of the dice to get one that will, Ivy pretty much was consistent in the OCing, they all did a decent job. I am sure there are more....hope this helps
Main difference for a casual user is that a Haswell CPU is about 10% faster than an Ivy Bridge CPU at the same speed. Also laptops with Haswell should use less energy and run a little cooler than with Ivy Bridge.
thanks for the replies ... i am working for sales so that many customer need to know the basic difference but i used to explain still was trying to find some better views so posted a question on the forum ...lol