okay so im trying to overclock my i76850k with asusx99-aii mobo

I used this video and copied his settings and got to 4.2

https://www.youtube.com/watch?v=2h8jWBd0XL4

I am trying to reach 4.5 and not sure what i need to do.. i tried changing the cores from 42 to 45 but my pc crashed while booting.. I am using the same settings in the tutorial and am running prime95 and it has not crashed yet with max temps hitting 53-55c. ( I did not change do anything to my ram tho) as in the video he changed his ram settings, but i left mine alone.

Any ideas on what I need to do so i can reach 45?