Question Using 7900XTX with daisy chained cables

[vladalex1956]

Hello everyone, I’ve read similar threads but still find myself confused, so I hope someone can clarify this for me.

I’m building a new PC and planning to use a Sapphire Nitro+ Radeon RX 7900 XTX GPU with a be quiet! Pure Power 12M 850W PSU. However, I noticed that my PSU has only two PCIe 12-pin slots, each with cables that have two 6+2-pin connectors (daisy-chained). I will attach an image with the cable.

The GPU requires three PCIe power connections and the Sapphire Nitro+ model is known to have the capacity to draw more power than other models (+450W).

I read a lot of takes about using daisy chained cables or not, but I still don't understand exactly why because there are a lot of contrary opinions.

From what I understand:

- A single PCIe 8-pin connector supplies up to 150W to the GPU

- Some say that daisy-chained cables from high-quality PSUs can safely handle more power (I read mostly about 288/300W), depending on the cable gauge and PSU design

The only specification I found about my PCIe cables is that they are 16-18 AWG, but I’m unsure how to calculate their maximum power handling capacity.

But if let's say we assume that each cable can handle 300W, does that mean my GPU would get:

- 300W (150W x 2 from the daisy-chained cable),

- 150W (from a single connector on the second cable), and

- 75W (from the PCIe slot),
for a total of 525W?

Or I could only get 150W in total from the daisy chained cable regardless?

I’d really appreciate it if someone could explain to me how this works and if I could use my GPU to full potential with this PSU.

Thank you for your help!

 

[beyondlogic]

Hello everyone, I’ve read similar threads but still find myself confused, so I hope someone can clarify this for me.

I’m building a new PC and planning to use a Sapphire Nitro+ Radeon RX 7900 XTX GPU with a be quiet! Pure Power 12M 850W PSU. However, I noticed that my PSU has only two PCIe 12-pin slots, each with cables that have two 6+2-pin connectors (daisy-chained). I will attach an image with the cable.

The GPU requires three PCIe power connections and the Sapphire Nitro+ model is known to have the capacity to draw more power than other models (+450W).

I read a lot of takes about using daisy chained cables or not, but I still don't understand exactly why because there are a lot of contrary opinions.

From what I understand:

- A single PCIe 8-pin connector supplies up to 150W to the GPU

- Some say that daisy-chained cables from high-quality PSUs can safely handle more power (I read mostly about 288/300W), depending on the cable gauge and PSU design

The only specification I found about my PCIe cables is that they are 16-18 AWG, but I’m unsure how to calculate their maximum power handling capacity.

But if let's say we assume that each cable can handle 300W, does that mean my GPU would get:

- 300W (150W x 2 from the daisy-chained cable),

- 150W (from a single connector on the second cable), and

- 75W (from the PCIe slot),
for a total of 525W?

Or I could only get 150W in total from the daisy chained cable regardless?

I’d really appreciate it if someone could explain to me how this works and if I could use my GPU to full potential with this PSU.

Thank you for your help!

easily explained

if the power supply has 2 8 pin headers of a single pci then the hardware in the psu can handle 300w max per cable. this will be factored in by the cable itself being a better awg to handle the load.

this threw me for a loop as well when NVidias 16 pin nonsense started.

so to clarify 1 cable with 2 8 pins = 300w
75w comes from the pci.
the last 8 pin 150w

the extra 100w headroom is to compensate for say spikes in power which happen with any card.

 

[Lutfij]

Welcome to the forums, newcomer!

You might want to read through this;
https://knowledge.seasonic.com/arti...ark-for-high-power-consumption-graphics-cards
^ see the standard layout.

https://www.bequiet.com/en/powersupply/4162
You should be able to use a standalone harness and a daisychained harness to meet the 3x8pin connectors on the GPU.

 

[ohio_buckeye]

Plug in both pci e cables and you’ll just need to use one of the daisy chains. My 7900xtx only requires 2 8 pins. My older 6800xt I just sold required 3 though but never had trouble using 2 dedicated and 1 daisy chain.

For what it’s worth I’m glad that AMD has stayed with the older 8 pin connectors. They’ve been around what 10 years or more and just work.