i5 is only dual core I think whereas i7 is Quad Core, but it goes much more beyond the amount of cores you have for example, speed, chip-types and so on.
I haven't had much experience with the new i5 and i7, but I believe:
i7 has 7 cores, i5 has 5 cores, and quad (meaning 4) has 4 cores.
i7 980X = 6 cores
i7 is = Quad 4 cores
i5 upto model 570 = dual core that means 2 cores and from i5 570 all r Quad core that means 4 cores
i3= dual core 2 cores....
i5 is only dual core I think whereas i7 is Quad Core, but it goes much more beyond the amount of cores you have for example, speed, chip-types and so on.
i 5 are dual cores and starting from model i5 750 they r all Quad cores......and all i7 except i7 980x are quad cores..... i7 980 is a 6 core processor.....