Good MB & RAM for 7800X3D?

[Zarax]

This is what the manual says:

 

[Zarax]

This photo shows the difference

None of the cables I got splits.

This is the other cable I have, both ends:

 

[Zarax]

As Tetras says, that does split and is the correct cable. You plug the long side of the cable into the PSU and on the other end you have the first 4+4 plug and then a short distance after the second 4+4 which go into the motherboard

Ok, I'm glad to be an idiot in this case and thanks for all the support!
Now, where should I plug it on the PSU side and should I plub both other plugs on the motherboard?

 

[Zarax]

It boots!
I will now install windows and ask more idiot questions about EXPO later on.

Thank you very much!

 

[Zarax]

Cheers guys, writing from the new rig.
Need to figure out why chassis fans aren't working and cooler seems a little loud at times while updating Windows but it seems to be working otherwise.
As a note of colour, the Corsair 5000D Airflow is a chonky boy! Makes my old coolermaster HAF seem tiny by comparison at that was a pretty big case when I got it...

 

[Zarax]

Looking online i think it has a fan controller.

This convo may help.

Connecting the fan hub to power I get the back fan working but nor the front one.
I successfully installed the RX7900GRE, all that's left is hard disk and transferring files/programs.

 

[Zarax]

Have you downloaded the icue software?..i'm assuming both fans connected to the pwm hub,powered by sata connector to psu and connected to fan header on mobo. does the icue software not pick up the hub?..if so, it should show the fans connected to it?

been awhile since looked at my 5000x setup and use rgb fans, so could be wrong. also think my fans were in a commander pro rather than the pwm hub, so might work differently

I haven't and would prefer to avoid anything not strictly necessary... I will look at the fans again this weekend when I have time.