Adapter cable (6 to 8 pin) for XFX RX 580

[eys]

Hi all,

I bought an XFX RX 580 GTS XXX ed 8GB (specs) and by mistake I thought it would come with a 6pin connector, instead it has one 8pin input. My PSU is a Corsair VX 450W (specs), which comes with only one 6pin PCIe cable and no 8pin ones.

Will any of these adapters work fine?
1x 6pin PCIe to 8PCIe
2x 4pin Molex to 8PCIe
2x 4pin SATA to 8PCIe

I read this thread and feel more confused; it was even suggested to just plug the PSU's 6pin cable in the 8pin input of the graphic card. I want to be sure that I don't damage any hardware.

I should specify that I'm building an external GPU setup, so my PSU only needs to power the card itself and a small adapter (PCIe riser).

Thanks for the help!

 

[dorsetknob]

You might want to trade up your PSU as 450w is recommended minimum.

 

[Cranky5150]

I agree, upgrade that PSU.

 

[Regeneration]

Your card came with double 6-pin to single 8-pin. A regular single 6-pin is capable of 75 watts. You need a new power supply.

 

[eys]

The minimum recommendations include other components, so the card should not need that much and I have nothing else to connect to that PSU.
The card can get 150W from the 8pin input and another 75W from the PCIe x16 slot on the adapter, half of what the PSU can provide.

Instead of the 6pin to 8pin I could use the 2x Moles to 8pin to provide enough watts?

Am I looking at this the wrong way?

 

[Caring1]

The minimum recommendations include other components, so the card should not need that much and I have nothing else to connect to that PSU.
The card can get 150W from the 8pin input and another 75W from the PCIe x16 slot on the adapter, half of what the PSU can provide.

Instead of the 6pin to 8pin I could use the 2x Moles to 8pin to provide enough watts?

Am I looking at this the wrong way?

You can use the Molex OR Sata options.
Are you running a PCI-e extension cable to the riser from the motherboard?
For an e-GPU an Nvidia card would have been more efficient due to lower power usage.

 

[eys]

You can use the Molex OR Sata options.
Are you running a PCI-e extension cable to the riser from the motherboard?

Yes, this one.
Do you know if there is any difference between the Molex or SATA options for my purpose?

 

[Flaky]

6pin in 8pin with "paperclip trick" > 6pin to 8pin adapter > dual molex to 6pin > dual sata to 6pin

 

[eys]

6pin in 8pin with "paperclip trick" > 6pin to 8pin adapter > dual molex to 6pin > dual sata to 6pin

why the dual molex/sata to 6pin instead of 8pin? Typo?

it seems counter-intuitive to me that the 6pin to 8pin with paperclip trick is better than all other options, particularly the dual molex/sata. This means that the card will receive enough power from the 6pin (plus PCIe slot)?

 

[xman2007]

I should specify that I'm building an external GPU setup, so my PSU only needs to power the card itself and a small adapter (PCIe riser).

You might want to trade up your PSU as 450w is recommended minimum.

I agree, upgrade that PSU.

Your card came with double 6-pin to single 8-pin. A regular single 6-pin is capable of 75 watts. You need a new power supply.

450w external PSU is not enough for a 580 on it's own?

it's not an orthodox setup but I would go with either the 6 pin to 8 pin PCIE adaptor or 2x4pin molex to 8pin pcie

 

[DR4G00N]

why the dual molex/sata to 6pin instead of 8pin? Typo?

it seems counter-intuitive to me that the 6pin to 8pin with paperclip trick is better than all other options, particularly the dual molex/sata. This means that the card will receive enough power from the 6pin (plus PCIe slot)?

6 pin & 8 pin pcie connectors are essentially the same, the extra pins are just a sense and a ground. Short the extra sense pin to ground and the card will see it as an 8 pin.

 

[eys]

Can I damage the graphic card if I just try connecting the 6pin in the 8pin slot (maybe with the paperclip trick if needed)? I guess, worst case it does not start due to low power? And in that case I'd go for the dual Molex to 8pin pcie option.

Thanks everyone for the help!

 

[Flaky]

Can I damage the graphic card(...)?

No, you can't. The cards are fairly idiotproof, and without full 8pin plugged they will either refuse to start, or be more power limited.

I guess, worst case it does not start due to low power?

The card can't know such thing as "low power". It can only sense two pins and see if they are shorted to ground (meaning connected), thus interpreting it as 6pin or 8pin plugged.


On 6pin, there are 3 wires carrying the 12V. With molex or sata, you have only two.
Use the 6pin if you can.

 

[Regeneration]

On AMD's website, the PSU recommendation is 500w and it is also noted the typical power usage of RX 580 is around 185w.

It's not just a matter of how many pins are there, but maximum rail output.

PCIe 6-pin = 75w
PCIe 8-pin = 150w

PSUs are designed for these standards.

Old PSUs capable of 150w via single cable usually come with double PCIe 6-pin connectors.

 

[eys]

Thanks everyone for the comments, I'll try plugging in the 6pin PCIe to the 8pin input (with/without short-circuiting the remaining two) and see how it goes.
Still waiting for the adapter to be delivered, this one will provide an extra 75W, so without that there's probably no chance of having enough power for the card. I can write back once I have all components and have plugged everything.

Interestingly the first answer in this thread points out that the actual wattage provided by 6 and 8pin PCIe is much higher than what is officially declared. Up to 195W for the 6pin (unfortunately the link in there is not working any more). If that's the case, potentially the card would get enough power from the PSU alone. I might trust myself to just plug the PSU and the card and see if the fans start (no adapter, no connection to laptop yet).

 

[Vya Domus]

6 pin adapters are fine when the card is under 150W TDP, the RX580 technically meets that requirement but it's at the limit of what I would comfortably use.

No, you can't. The cards are fairly idiotproof, and without full 8pin plugged they will either refuse to start, or be more power limited.

They are not idiot proof and this is just wrong. If the connector isn't fully plugged and the system manages to start you run into the risk of burning the connector away because same current now has to go through less of a contact area, in facts that's how PCIe connectors on cards usually die. Careful with this dangerous advice.

 

[Flaky]

Not fully plugging the connector can happen on any connector, we might just as well say that none of them is safe in that regard.
Keeping a connector loose is... well... one step beyond what I'd call being a conventional idiot.