Black screen, GPU fans going mad, PC still working in background

JLArranz said:

I don't know or didn't know this technology, but I've researched it a bit. I recommend reading the 2nd link complete, and the 3rd too specially the functions of the sense cables. For example S3 and S4 must be grounded to provide the maximum power, obviously the PSU will only ground them if it can provide those 600W, and what if there isn't connection? (one or two of them are open by misdesign or accidentally, like the connection being poor and getting loose with the heat, expansion coefficients etc). Similar reasoning goes for the other 2 cables, that are optional according to the 3rd link.

Google Search

https://www.reddit.com/r/nvidia/comments/16hxo2g/for_the_4070_fe_what_do_the_sense_pins_on_the

ATX 3.0 Power Supply Connectors and Pinouts

Intel's ATX 3.0 specification, connectors and pinouts. Diagram, pinout and wire colors of PCIe 12VHPWR auxiliary connector.

www.smpspowersupply.com

It seems that the Corsair cable doesn't connect two of the "sense pins" (most likely the optional ones) maybe under the assumption they don't do anything, but they do things. The nVidia cable (provided with the card) does connect the four pins. There's also a potential compatibility problem of a newer connector spec that has shorter pins, with older cables designed for longer pins. The result would be, again, no use of some pins.

It seems that all this is for a new thing I'd call "newer power security and management system".

As for using old PCI-E connectors, Idk if:

- They don't have any "power security and management system", not the new for sure but not an older one either.
- They have an older "power security and management system".

...but three 6+2 or 8 pin cables/connectors shoud be used, as the card's TDP is 450W and each connector is specified to provide 150W.

I'd research if the card can live w/o or with the old "power security and management system", if it works better or worse and if it wears the hw more or less (at least theoretically).

The whole story about not using pins or (even worse) not doing connection for a lengths issue, it's sooooo absolutely cheap... There isn't high bandwidth data involved (like in SATA or USB), is it? In this hypothetical case any physical difference may be critical, otherwise you only have to care about two things: physical electrical contact exists (lol) and it's strong.

Click to expand...

There were older cables that lacked the sense pins but that had the same 16 pin connector. (An RTX 3090 ti used one.) But if a cable is listed as 12VHPWR, it shouldn't be one of the older type.

JLArranz said:

I don't know or didn't know this technology, but I've researched it a bit. I recommend reading the 2nd link complete, and the 3rd too specially the functions of the sense cables. For example S3 and S4 must be grounded to provide the maximum power, obviously the PSU will only ground them if it can provide those 600W, and what if there isn't connection? (one or two of them are open by misdesign or accidentally, like the connection being poor and getting loose with the heat, expansion coefficients etc). Similar reasoning goes for the other 2 cables, that are optional according to the 3rd link.

Google Search

https://www.reddit.com/r/nvidia/comments/16hxo2g/for_the_4070_fe_what_do_the_sense_pins_on_the

ATX 3.0 Power Supply Connectors and Pinouts

Intel's ATX 3.0 specification, connectors and pinouts. Diagram, pinout and wire colors of PCIe 12VHPWR auxiliary connector.

www.smpspowersupply.com

It seems that the Corsair cable doesn't connect two of the "sense pins" (most likely the optional ones) maybe under the assumption they don't do anything, but they do things. The nVidia cable (provided with the card) does connect the four pins. There's also a potential compatibility problem of a newer connector spec that has shorter pins, with older cables designed for longer pins. The result would be, again, no use of some pins.

It seems that all this is for a new thing I'd call "newer power security and management system".

As for using old PCI-E connectors, Idk if:

- They don't have any "power security and management system", not the new for sure but not an older one either.
- They have an older "power security and management system".

...but three 6+2 or 8 pin cables/connectors shoud be used, as the card's TDP is 450W and each connector is specified to provide 150W.

I'd research if the card can live w/o or with the old "power security and management system", if it works better or worse and if it wears the hw more or less (at least theoretically).

The whole story about not using pins or (even worse) not doing connection for a lengths issue, it's sooooo absolutely cheap... There isn't high bandwidth data involved (like in SATA or USB), is it? In this hypothetical case any physical difference may be critical, otherwise you only have to care about two things: physical electrical contact exists (lol) and it's strong.

Click to expand...

Tbh, it’s all a bit technical for me!
My Corsair RM850X is APX 3.1 and PCI-E 5.0 compatible. I have a MSI RTX4090 Gaming Trio.
I am using 3 separate cables from PSU to the MSI adaptor.
Is there a good reason to change the cables to what is being suggested here, do you think?

imacken said:

Tbh, it’s all a bit technical for me!
My Corsair RM850X is APX 3.1 and PCI-E 5.0 compatible. I have a MSI RTX4090 Gaming Trio.
I am using 3 separate cables from PSU to the MSI adaptor.
Is there a good reason to change the cables to what is being suggested here, do you think?

Click to expand...

I've read the thread more carefully and with more knowledge. You were using 2 PCIe 8 pins and now you're using 3. This is correct and likely (I don't know all!) it has fixed your issue for the following reason: as each PCIe 8 pins power connector is specified to supply up to 150 W, and your 4090 can consume up to 450 W (although for the looks of your problem, it isn't very frequent that it surpasses 300 W), you've fixed the (relatively infrequent) power shortages you were having.

(note: PCIe 8x cables can actually carry more than the said 150 W, what means "actually"?: my car can go say at 140 km/h and the speed limit is 120 km/h, but with two differences: 1) the traffic police is absolutely always watching 2) it doesn't send tickets, instead it takes the control of the car/card, but not to decelerate it to 120 km/h or 300W, instead it stops the car/disconnects whatever in the card, hence the black screens)

Some users thought you were having a problem with the "modern cable" instead, that seems widespread, and they were quite sure about that. I was also sure when I was writing my previous post, and I was thinking you were using the PCIe 8x connectors (first 2 afterwards 3) as a workaround.

I cannot see in the Corsair RM850X specs RMx Series™ RM850x — 850 Watt 80 PLUS Gold Fully Modular ATX PSU (EU) the "modern cable", I can see 3 EPS, 14 SATA, 4PCIe etc but not the "modern cable", so Idk if you have the option anyway.

In case you actually have it or for readers considering options, I've only read the summary in the 3rd link of my previous post. I like some things and I dislike others, specially the concept of allowing surge current. Considerations from here are infinite like: is the surge allowed and "secured" through a special new circuit? does only the "modern cable" enjoy it and the rest of the PSU has the normal OCP (over current protection) that would shut down? are the surges justified from a technical standpoint or are they allowing defects through a new PSU spec? or the contrary option, is it a brilliant solution to some performance difficulties? I'm not enough in the know.

Sooooo, if you don't have problems now, enjoy your new setup! :)

imacken said:

Tbh, it’s all a bit technical for me!
My Corsair RM850X is APX 3.1 and PCI-E 5.0 compatible. I have a MSI RTX4090 Gaming Trio.
I am using 3 separate cables from PSU to the MSI adaptor.
Is there a good reason to change the cables to what is being suggested here, do you think?

Click to expand...

I wonder what you have.

RM850X:



I don't think that this is ATX 3.1.

RMe850X:



Notice the socket at top right.

If you have such a socket, I recommend getting the cable that uses it.

If not, I suggest using the official Corsair cable, even though it uses only two PCI-E ports.

I dislike adapters. But your current approach using the adapter supplied with the card and 3 PCI-E cables should work well. I think that your former connection using two connecters off a single PCI-E cable was probably OK too, as long as it didn't start any fires.

Does Reliability History have entries at the time of the problem ?
In the Search box,start typing ---reliability ---to access it.

bobkn said:

I wonder what you have.

RM850X:

View attachment 144170

I don't think that this is ATX 3.1.

RMe850X:

View attachment 144171

Notice the socket at top right.

If you have such a socket, I recommend getting the cable that uses it.

If not, I suggest using the official Corsair cable, even though it uses only two PCI-E ports.

I dislike adapters. But your current approach using the adapter supplied with the card and 3 PCI-E cables should work well. I think that your former connection using two connecters off a single PCI-E cable was probably OK too, as long as it didn't start any fires.

Click to expand...

Yep, you’re correct. I have the top image version of the RM850X. Didn’t realise that the specs had changed on that since my purchase in 2020. It’s not ATX 3.1.

joeandmarg0 said:

Does Reliability History have entries at the time of the problem ?
In the Search box,start typing ---reliability ---to access it.

Click to expand...

Thanks, but no, nothing of interest there.

Just a follow up on this. Since I changed to using 3 separate cables from the PSU to the GPU (rather than the 2 with one piggy backing as 2) the problem has not reoccurred.
So, 2 weeks of trouble free use!