Really Simple question because I'm dumb

[Burnedice25]

Hey there!

I've been building PCs for 10 years, and this is a stupid question, but in all that time I've never worked with a fully modular PSU, and while upgrading my friend's rig, iIve into a bit of trouble

I'm installing a GTX 1080 we got for a good price, and after inserting the card into the MOBO, I've found he doesn't have any spare cables (he was previously running a low power card). No problem, i'll buy some PCIe cables online and they'll be here in a few days, annoying but whatever.

When searching online, I've found what cables I need. Corsair type 4 PCIe cables for the RM550x PSU (if someone could double check that too, that would be great, im reasonably confident but again never worked with these PSUs before)
PSU info sheet here: https://www.corsair.com/corsairmedia/sys_master/productcontent/RMx_2018_Manual.pdf

The problem occurs here... The GPU needs a 8pin and a 6 pin, but on the PSU there is only one 8 pin available on the PCIe section of the ports.

 

The CPU is of course populating the other 8 pin, leaving only 8 free. (See attached picture for reference.)

But I've looked online and there's plenty of people running this exact combination of parts, so I have no idea what I'm missing here, any help would be appreciated 

 

 https://www.google.com/url?sa=i&url=https%3A%2F%2Fwww.scan.co.uk%2Fproducts%2F550w-corsair-rmx-series-rm550x-full-modular-80plus-gold-sli-crossfire-single-rail-458a-140mm-fan-atx&psig=AOvVaw2TfWxcmKQ2hqqwRawNpI1e&ust=1681656049474000&source=images&cd=vfe&ved=0CBAQjRxqFwoTCLiem42PrP4CFQAAAAAdAAAAABAE
(EDIT: apologies, the picture wont attach so here is a link)

Edited April 15, 2023 by Burnedice25
(EDIT: apologies, the picture wont attach so here is a link)

[mariushm]

The connectors on the power supply for the cables going to video card will be 8 pin just like the cable with the EPS (CPU) connectors.

The same connector is used on the power supply.

 

The connectors at the end of the cable that go into motherboard or video card are different.  You will get a cable with 2 pci-e 8 pin connectors, but most likely at least one of them will be 6+2, as in the connector can be separated in a 6 pin part and a 2 pin part, for backwards compatibility with video cards like yours.

 

For pci-e cables, Corsair Type 3 and Corsair Type 4 should both work, the difference between them is just which of the 4 available 12v pins in the EPS connector are used to connect the 3 12v wires in the cable.   Type 3 uses pins 1,3,4  while type 4 uses pins 1,2,3  .... the power supplies don't care and make no difference between those pins, all four pins are connected together internally and there's no way of knowing which of the pins are actually used.

 

Cables with sata and molex connector are basically identical as well, so type 3 and type 4, doesn't matter.

 

Type 3 : https://pc-mods.com/blogs/psu-pinout-repository/corsair-psu-type-3-cables-pinout

Type 4: https://pc-mods.com/blogs/psu-pinout-repository/corsair-psu-type-4-cables-pinout

 

The differences between versions are in the 24 pin atx connector, in type 4 there's extra sense wires connected to 3.3v, 5v and 12v pins so that the power supply can give more accurate voltages.

 

[Burnedice25]

2 minutes ago, mariushm said:

The connectors on the power supply for the cables going to video card will be 8 pin just like the cable with the EPS (CPU) connectors.

The same connector is used on the power supply.

 

The connectors at the end of the cable that go into motherboard or video card are different.  You will get a cable with 2 pci-e 8 pin connectors, but most likely at least one of them will be 6+2, as in the connector can be separated in a 6 pin part and a 2 pin part, for backwards compatibility with video cards like yours.

 

For pci-e cables, Corsair Type 3 and Corsair Type 4 should both work, the difference between them is just which of the 4 available 12v pins in the EPS connector are used to connect the 3 12v wires in the cable.   Type 3 uses pins 1,3,4  while type 4 uses pins 1,2,3  .... the power supplies don't care and make no difference between those pins, all four pins are connected together internally and there's no way of knowing which of the pins are actually used.

 

Cables with sata and molex connector are basically identical as well, so type 3 and type 4, doesn't matter.

 

Type 3 : https://pc-mods.com/blogs/psu-pinout-repository/corsair-psu-type-3-cables-pinout

Type 4: https://pc-mods.com/blogs/psu-pinout-repository/corsair-psu-type-4-cables-pinout

 

The differences between versions are in the 24 pin atx connector, in type 4 there's extra sense wires connected to 3.3v, 5v and 12v pins so that the power supply can give more accurate voltages.

 

Sorry, just to clarify...

I get one cable, with one 8 pin connector on it for the PSU side, but has 16 pins on the other side for the GPU (assuming 6+2, yadda yadda)