Let's assume the board can't give 1.15 becouse it's too low. But even when i pump more voltage it's almost the same thing, but now exactly the same difference between bios vcore and cpuz. I have to measure the vcore with DMM. If you are wright it means i can kill the chip becouse i don't know the real vcore.
I Have doubts becouse my cpu has the same FPO as another two cpus and both of them can do 4GHz stable with 1.28V. I don't think mine need 1.36V for 4G.