Z390 AORUS PRO - am I plugging the power cables in correctly?

[csber3]

So I just got a Gigabyte Z390 Aorus Pro and there are two slot (is that the right word) for the power cables - not counting the big wide one. One labeled ATX_12V_2X4 and the other labeled ATX_12V_2X2. Do I need to plug a power cable into both? I have a Corsair 850 Watt RM850x PSU and have plugged it into the ATX_12V_2X4 slot but do I need to do the other as well? If not, what's the other slot for?

Apologies if this is a completely newbie question - it's the first time i've actually noticed the two slots.

 

[EsaT]

8 pin EPS12V connector is enough until going for heavy overclocking.

 

[orbitalwalsh]

if you can plug in the extra 4 then do so .

as esat mention, primary job is supply extra power . It also spreads the load of the power to the socket < but as mentioned , plays more effects with heavy OC and AVX loads.

irony is, really need a seperate railed PSU to take advantage of this .

if you had a thermal gun, you'd notice 8 pin is slightly lower in temps when pin it and 4 pin plugged in - again, most users wouldn't bat an eye-lid . though will try and dig out the snaps as they are pretty cool