Corsair HX 1200 | One Pcie cable won’t supply 2 GPUs

[RealSwissMiner]

Fellow miners

I have a problem with the Corsair HX 1200 PSU. It works perfectly fine with one GPU per PCie cable. When I put a second GPU to the same cable the card doesn’t even start. It’s not a card problem as I switched them and observed the same behavior.

My ressearch told me already to change the button at the back of the PSU to single instead of multipe but It didn’t help.

Anyone faced this issue already or has any suggestions?

[1714982427]

1714982427

[m1n1ngP4d4w4n]

2 card on the same cable is too much that's all there is, don't use more than 1 per card.

[RealSwissMiner]

2 card on the same cable is too much that's all there is, don't use more than 1 per card.

So with a maximum of 5 possible connected pcie cables you want to tell me that I cannot put more than 5 cards - even if I only put GTX 1060 which would not even reach half of the PSU capacity?

[m1n1ngP4d4w4n]

The PSU you have it's 6x VGA power outlet, so 6 cards, i guess with 1050/1060 you can put 2x card per cable, but 1070 or above would be pushing it imho.

[wacko]

I have a problem with the Corsair HX 1200 PSU. It works perfectly fine with one GPU per PCie cable. When I put a second GPU to the same cable the card doesn’t even start. It’s not a card problem as I switched them and observed the same behavior.

That's weird. I don't have this particular PSU to test right now, but I've got a Corsair RM750i and it definitely works fine with 2 cards per cable — I remember connecting 4* rx 480 to that PSU, each card with a single 8-pin connector, and it only has 2 cables (with 2 pci-e connectors each). Maybe something's wrong with the PSU? Do all the connectors actually work?

[RealSwissMiner]

I have a problem with the Corsair HX 1200 PSU. It works perfectly fine with one GPU per PCie cable. When I put a second GPU to the same cable the card doesn’t even start. It’s not a card problem as I switched them and observed the same behavior.

That's weird. I don't have this particular PSU to test right now, but I've got a Corsair RM750i and it definitely works fine with 2 cards per cable — I remember connecting 4* rx 480 to that PSU, each card with a single 8-pin connector, and it only has 2 cables (with 2 pci-e connectors each). Maybe something's wrong with the PSU? Do all the connectors actually work?

Yes, its powering 5 cards but if I put the sixth card to the second pcie connector it doesnt power up. The card gets no power whatsoever it actually looks like the card is dead - the system only starts with 5 GPUs. Very weird

[Mattthev]

Yes, its powering 5 cards but if I put the sixth card to the second pcie connector it doesnt power up. The card gets no power whatsoever it actually looks like the card is dead - the system only starts with 5 GPUs. Very weird

I have this same PSU and 6 cards is no problem at all. Have you switched PSU to single rail?

[Bakhtra]

I use Corsair RM1000X powering 7 RX 580, each cable powering 2  GPU, and its stable as hell, with 850w from wall.

[RealSwissMiner]

Yes, its powering 5 cards but if I put the sixth card to the second pcie connector it doesnt power up. The card gets no power whatsoever it actually looks like the card is dead - the system only starts with 5 GPUs. Very weird

I have this same PSU and 6 cards is no problem at all. Have you switched PSU to single rail?

Yes I switched it to single and also unplugged it just to be sure that the change is reflected. Still didn’t change anything.
Other than that there is not much to configure. The 850 PSU just works fine with the 6 cards @530 watt, really funny stuff

[Pennywis3]

2 card on the same cable is too much that's all there is, don't use more than 1 per card.

I use only one GPU per cable also, but connecting two gpu's with 8 pin each shouldn't be a problem, as most cables are rated 300w+.
But for obvious reasons i wouldn't recommend it also.

[mdizzlebizzle]

I have 16 rigs with this PSU, using 3 cables to power 6 gpus.. havent had any issues. What are your power limits set to?

[RealSwissMiner]

I have 16 rigs with this PSU, using 3 cables to power 6 gpus.. havent had any issues. What are your power limits set to?

Power limit on the cards? Its an AMD rig all cores run with 1150 Mhz the entire rig consumes 530 Watt ( will be extended in the future). The consumption can really not be a problem especially considering that the 850 PSU just works fine and powers all 6 cards. Just replacing the PSU ends in only 5 gpus starting.

I also don’t believe that the PSU has a technical problem as everything else just works fine ( runs stable for 3 days on a test machine)

[m1n1ngP4d4w4n]

Ok so maybe a faulty GPU then.

[RealSwissMiner]

Ok so maybe a faulty GPU then.

No, all 6 cards just work fine with the other PSU. Best is really to never touch a rig that is stable you always encounter problems if you change somehing hardware related.

[m1n1ngP4d4w4n]

Ok so maybe a faulty GPU then.

No, all 6 cards just work fine with the other PSU. Best is really to never touch a rig that is stable you always encounter problems if you change somehing hardware related.

If a 2nd card on the same cable doesn't start, the power pulling is too much and the gpu don't get enough power, are you using powered risers and additionnal PCI power on the motherboard ? it can help smooth the power draw accross all the PSU outputs.

And what you say is true, never touch something that work 

[wacko]

If a 2nd card on the same cable doesn't start, the power pulling is too much and the gpu don't get enough power

GPUs don't need much power to start, it's not like hard drives or anything with a motor, they consume just a few watts when you turn the system on.

[m1n1ngP4d4w4n]

If a 2nd card on the same cable doesn't start, the power pulling is too much and the gpu don't get enough power

GPUs don't need much power to start, it's not like hard drives or anything with a motor, they consume just a few watts when you turn the system on.

True, gpu don't consume much when turned on, but it's weird the GPU doesn't start when it's put in combo with another one, but work perfectly when solo on a cable, maybe there is some sort of protection to protect the PSU or the GPU.

What GPU's OP is using, how many 8 and 6pin power connector per card (which brand/model), what does he use to separate the power (Y cables ?)

[RealSwissMiner]

If a 2nd card on the same cable doesn't start, the power pulling is too much and the gpu don't get enough power

GPUs don't need much power to start, it's not like hard drives or anything with a motor, they consume just a few watts when you turn the system on.

True, gpu don't consume much when turned on, but it's weird the GPU doesn't start when it's put in combo with another one, but work perfectly when solo on a cable, maybe there is some sort of protection to protect the PSU or the GPU.

What GPU's OP is using, how many 8 and 6pin power connector per card (which brand/model), what does he use to separate the power (Y cables ?)

They are all Sapphire RX 570 cards (6) and working with only the 8pin connector branched. Pcie powered with a different power cable for all of them.

Separating power was not necessary as I only connect the second 8 pin connector of the PSU cable to the second card and it was working fine. As I previously wrote with the 850 Watt unit everything works perfectly fine.

[m1n1ngP4d4w4n]

I see,

Well never tried to connect only one power input of a GPU, there is obviously something blocking you to do this, you probably need a Y cable to double properly the connectors, and plug all of them. I don't use AMD cards. but there is something blocking you, does the rig make the POST properly ? you crash @ windows start right ? did you tried safe mode to see if it crash too ?

[RealSwissMiner]

I see,

Well never tried to connect only one power input of a GPU, there is obviously something blocking you to do this, you probably need a Y cable to double properly the connectors, and plug all of them. I don't use AMD cards. but there is something blocking you, does the rig make the POST properly ? you crash @ windows start right ? did you tried safe mode to see if it crash too ?

No its not crashing the 6th card is just not powered. I can start mining with the 5 GPUs no issues there everything very stable.
I have to check if some Y cables were included but this is just so weird. And obviously shutting down the rig and trying to solve this problem is annoying and downtime which is never good.