Overclocking an Aurora R5

[Yrrebpsar]

So I got a new Alienware Aurora r5 a couple of weeks ago. Im quite new at overclocking, and I am having trouble over clocking the computer. It runs at 3.4 Ghz regularly, but Dell claims it can be overclocked to 4.2 Ghz. Whenever I go to the BIOS, the overclocking option is unselectable, and is stuck on disabled. Is this a glitch, a manufacturing error, or am I supposed to do this with a different method?

Specs:
Nvidia 1080 founders
16GB RAM
Intel i7

Notes: done all the tests for overclocking, and the worst temp was 68 degrees. Just need to know how to overclock it.

 

[Kenrou]

Which version CPU did you pick ? if its the 6600/6700 it's locked and you wont be able to overclock, you need a 6600k/6700k.

http://www.dell.com/uk/p/alienware-aurora-r5-desktop/pd.aspx

BIOS something like this ?