i3 is also a dual-core cpu but it's too better than other dual-cores cpu's because of latest use of 32nm (nanometer) where the old dual core is 45nm.i3 has 4 threads which is helps in most application's and normal dual core has only 2 threads.i3 has 2 cores but these two cores are double time faster than normal dual core.
I3 2100 can beat e8600