Psu cpu connections.

CD32 · 15 Jan 2021 at 20:07

I'd start off by saying belated happy new year everyone but think I'll hold off on that one. A query if someone can help. Starting a new build..to replace my ageing 4770k. Ryzen 5600x. MSI x570 Tomahawk mobo & swapping out the psu for corsair RM850. My first modular psu. The thing is...on the motherboard there are two cpu connections. Cpu pwr 1 & cpu pwr 2. Cpu 1 is 8 pin & cpu 2 is 4 pin. The psu does not come with a 4 pin cable...just an 8 pin...labelled cpu. Am I looking at getting another cable with 4 pins? Seems strange I'd have to.

Also...the motherboard power cable..the end that plugs into the psu has two type 4 connectors...one short & one long..do I plug both of these in? Might sound a stupid question but you never know..& it's been 7 years since my last build!

Any advice appreciated..tia..Andy

EsaT · 15 Jan 2021 at 20:54

Forget that 4 pin ATX12V connector.
It's marketing scammers wasting money into useless things not needed by 99+% of users.

Drumroll · 15 Jan 2021 at 21:07

The cable for the CPU actually splits in 2 x 4pin. (only one side should fit properly. Try both, don't panic if the first doesn't connects. The other side will.

For the motherboard, both need connecting.
My ATX cable (new corsair here too), was a bit hard to connect to the motherboard. May happen to you, may not.

CD32 · 16 Jan 2021 at 14:36

Thanks for the replies EsaT/MrPotato. I had to look to see that cable splits! Therefore I can plug it into cpu2 afterall. Or not if it's not needed as suggested. Did Google this first but came back with conflicting results..no it's not needed..yes it was needed for someone for stability..etc. Anyway..the cable is there afterall should I ever need it! cheers..Andy.

pastymuncher · 17 Jan 2021 at 18:35

Don't split the cpu connector, just insert it as a 8 pin into the 8 pin socket. You only need the extra 4 pin for extreme overclocking (as in LN2/Phase). Keep the motherboard connector together as a 24 pin plug.

CD32 · 20 Jan 2021 at 18:04

Sorry for the late reply pastymuncher...didn't think anyone else would be posting. Yeah I did mean plugging the eight pin one in & splitting a second cable so they're both plugged in. But if not needed. Should have came here first instead of googling because I see my question has been asked & answered a couple of times before! Cheers again...Andy

Raiden85 · 24 Jan 2021 at 02:14

The main big 8 pin is 100% required but the extra separate 4 pin connector is optional, the 8 pin alone will provide way more power than you'll need. As said above unless you decide to go sub zero cooling and then putting an insane amount of power through the CPU then you may need it.

Even my overclocked 5950X doesn't go near to using all the power that the 8 pin provides.

pp111 · 24 Jan 2021 at 07:37

CD32 said:
Thanks for the replies EsaT/MrPotato. I had to look to see that cable splits! Therefore I can plug it into cpu2 afterall. Or not if it's not needed as suggested. Did Google this first but came back with conflicting results..no it's not needed..yes it was needed for someone for stability..etc. Anyway..the cable is there afterall should I ever need it! cheers..Andy.

I have two identical PC's, one has it connected, one does not. There have been no stability problems with the PC that does not have it connected. I think the message with this one is - if you have the cable then connect it, if you don't then don't bother.

CD32 · 24 Jan 2021 at 16:11

Raiden85 thinking about it...agree with you that the 4 pin isn't required.....given that my 4770k mobo only has the eight pin yet the processor draws more power than the 5600x.

Agree with you too pp111....I have the extra connection....may as well plug it in anyway as per mobo instructions. Cheers all!