Thks guys,
Alright, made a bench with Cinebench in my two Macs, my IMac late 2013 with a DC i5 which handle 4k OK, and to my MBP with QC i7. The results are that the MBP got better results AND have a discrete GPU.
So I assume is not the CPU, neither the memory because both are 1600Mhz.
May be...