Here's a note about the i5.
by R. Proffitt - 11/9/12 9:03 AM
In Reply to: i5 vs i7 for gaming and light video/music editing? by ET_CaughDrop
"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. "
So for gamers, they often get 1,000 buck CPUs and then cut the GPU where the real action is.