gomesyo :
I use a single 1080p but i want to play without problem 60fps at least, in high xD..the 6600 is far batter than i5 2500 right?
At 1080p, you will see a gain in FPS between a 2500 and 6600, perhaps a 5% improvement. When CPU speed and generation start to mean less is when you go beyond 1080p and use higher quality and AA settings, which put more stress on the GPU (I still have a 2500K build that is now a backup gaming rig...see my sig below).
So from your seat, you will gain in FPS both from a new Skylake CPU and motherboard and the 1060 to probably come real close in performance to just upgrading to a 1070 on the 2500 (if not equal it). These kinds of comparisons are never done and would be very interesting to see. I'm just basing my opinion on my personal experience with upgrades over the years.