Depends on use. For example, you'ver read this?

by R. Proffitt Moderator - 12/9/12 12:08 AM

In Reply to: More RAM or more cores? by c_alva

"Our tests demonstrate fairly little difference between a $225 LGA 1155 Core i5-2500K and a $1000 LGA 2011 Core i7-3960X, even when three-way graphics card configurations are involved. It turns out that memory bandwidth and PCIe throughput don't hold back the performance of existing Sandy Bridge-based machines. "
http://www.tomshardware.com/reviews/gaming-cpu-review-overclock,3106-4.html

Without knowing the app and such, how can anyone answer?
Bob