More Cores Or More RAM?

So i was just wondering since the phones now are coming equipped with 4 cores and now samsung launched s4 with 8 cores which phone is much snappier ?the phone with more ram or with more cores?
For eg. a phone has a 1.5 ghz dual core processor with 2 gb ram or the phone with 1.5 ghz quad core with 1 gb ram?