EASY Modular PSU Cable Question

[Action_Johnson]

I know this is going to sound dumb, but I've never had a modular PSU before. 

Got in the mail a Corsair 4000D, RM850X, and a handful of AF120's in the mail today, and before I rebuild my PC into the new case and PSU, I've realized the manual doesn't specify if it's OK for me to use a single PCI-E splitter cable for the GPU. Is that how it's designed to work? 

 

I'm planning on picking up a 3080 when they're eventually available in a month or two from now and I don't want to blow up the PSU or the wiring because I'm drawing too much current in those cables. It looks like the single 8 pin goes into the PSU side, while the dual 8 pin goes to the video card? That can't be right. aren't I supposed to have 2 PCI-E cables going into the card?

 

Manual also doesn't specify what this 6+2 or 4+4 stuff means. Never seen a modular unit before, always had to stuff the extra cables somewhere.. 

 

 

[The_russian]

That's not unique to modular power supplies, a lot of normal ones also have that type of cable now. Personally for a higher TDP card like the 3080 I would use 2 separate cables just to be safe, that also has the benefit of looking cleaner than using the pigtail cable. 

[-rascal-]

I agree with @The_russian RTX 3000 series suck A LOT of power / current.

Play it safe, and use two (depending on which RTX 3080 / 3090 you get, can be three) PCI-E power connections.

[LUUD18]

I was also going to buy this PSU.

Where can I get a second cable? I think it is quite strange that a 850w PSU doesn't include two cables.

 

Edit: Nvm I see that they include 3 cables.

[Action_Johnson]

OK good to know!

 

I'll use the pigtail for my 1660 Super, as it doesn't draw a whole lot of electricity, and I'll get a couple of standard non-pigtail PCI-E cables from Corsair for when I eventually get a beefier video card

[Action_Johnson]

OK just finished taking everything out, and putting it back together. It was a royal pain in the butt. 

 

On the back bottom right where it says 6+2 PCI-E and 4+4 CPU, the right side connector won't power a video card, despite the label saying it would.

 

I really wish each port on the back of the PSU was labeled individually, the way it is now, it makes you assume that you can just plug the CPU or PCI-E power plugs wherever you want, when in reality, that's not the case, and it's not very specific either. 

[OrionFOTL]

On 10/3/2020 at 8:11 AM, Action_Johnson said:

Manual also doesn't specify what this 6+2 or 4+4 stuff means.

A 6+2pin PCI-E cable has a 6pin portion and a dangling 2pin portion, which you can connect to the 6pins to make it an 8pin cable, so you can use it with graphics cards that have a 6pin port or an 8pin port. Same goes for the 4+4pin CPU cable or the main ATX 24pin (20+4pin) cable.

 

On 10/3/2020 at 8:43 PM, Action_Johnson said:

and I'll get a couple of standard non-pigtail PCI-E cables from Corsair for when I eventually get a beefier video card

Why not just use two of the six PCI-E cables you already have, instead of ordering additional two non-pigtail ones?

 

21 hours ago, Action_Johnson said:

On the back bottom right where it says 6+2 PCI-E and 4+4 CPU, the right side connector won't power a video card, despite the label saying it would.

21 hours ago, Action_Johnson said:

the way it is now, it makes you assume that you can just plug the CPU or PCI-E power plugs wherever you want, when in reality, that's not the case

That is the case though. Any of the 8pin ports on the PSU can power either a CPU cable or a PCI-E cable. They're all identical. If something doesn't work, you're either doing something wrong, or using the wrong cables.