...if you're doing something that requires four cores [not much software around a.t.m.] you will need four cores.
In my opinion Intel devices are overpriced, need more expensive motherboards and process info in an inferior manner [wasting clock cycles].
Don't just go n quoted speeds, that just counts the cycles. AMD are more efficient processors. Intel's method of comparison is unfair, in this respect.
I'd stay with AMD and ignore what Intel say.