BIOS and CPU-Z not matching?

[Keod2]

Ok so I decided to overclock my CPU so I went straight for a pretty bog standard 4.2GHz @ 1.15V in the BIOS yet when I run CPU-Z it states it's running at 4.2Ghz @ 1.080-1.072V (flicks between the two) and yes this is under load in Prime95.

So I'm rather confused as to what is happening here???
Either way its been stable for 8hours under Prime95 Large FFTS over night, but I am curious which is the correct "reading".

Spoiler

 

[Keod2]

What should I set the LLC to to compensate? Also does this mean the CPU is stable with 1.072V @ 4.2GHz?

 

[Keod2]

hmm a valid point although I don't own one lol :/ I'll try a middle figure and see what it says