Haswell northbridge oc?

[Kaitodesu]

So I'm using a g3258 paired with an asrock b85 killer. it has this automatic oc function which i did a little manual ocing myself and currently running at 4.5ghz, 1.3v however i noticed this northbridge overclock setting where it bumps itself from 32 to 39 when using a automatic oc preset. may i know what does it do and will i benefit from gaming with a northbridge oc? i did some googling and most of the forum posts were for really old amd chips
specs:
g3258 3.5ghz 1.3v 
asrock b85 fatality killer
gtx 680 ekwb
hyperx savage ddr3 1600mhz
custom loop

[TheGamingBarrel]

It is overclocking your cache.