ASUS Z97 EATX12V socket question

[The Orig Ralph]

1st, i should probably alert you, i'm a 65 yr old fart that is electronically illiterate, attempting a DIY computer build

i've got an ASUS Z97M-Plus MB, and have gone through the manual but the issue is basically i'm still new at this (this is my first build).

I'm using a Seasonic SSP-450RT PSU, a totally non-modular psu.

In going thru the asus manual, when i come to the EATX12V socket (image of asus manual page below)

and below is the actual socket

the confusion comes from the fact that i've got two plugs on the seasonic harness that could and do fit into that socket.
one is a 6+2 plug, marked as "PCI-E" - below is the schematic from seasonic on this harness plug

and here is a pix of that 6+2 "PCI-E" plug

the second plug on the seasonic harness is a split or double four pin plug, schematic below

and a picture

The seasonic came without any kind of a manual (in fact came in a plastic bag, period, no box etc) fm Newegg, i had to dig those schematics up on their website.

my question is, which harness plug should i use in that socket - it's the only one i'm not certain of, and both actually fit into the socket and latch in securely. I suspect both would work, but if that's the case, which would be the better choice?

thanks for your patience in reading this "fred flintstone" presentation -

 

[Tradesman1]

The split double 4, the 6+2 PCI-E is for PCI-E graphics cards that take either a a 6 pin or 8 pin power input play, on your 4+4 you put them side by side w/ the outer clips together then insert so those slip over the protrusion on the outer edge of the 8 pin socket (towards the side of the mobo

 

[The Orig Ralph]

thanks -

 

[Tradesman1]

No worries