RTX 5090 LC Red LED flashing during gaming load

[sebbebro]

So I have the 5090 LC and a 1200W ASUS TUF Gold PSU. When running heavier games the red light flashes. Isn't there supposed to be a green light when the cable is seated properly. I've used 2 different 12VHPWR cables that were included with the same PSU. Reseated both of em twice, no green light.

It's probably worth to mention that Pin 6 is almost always around 3-4A when every other pin is around 8-9A. I have seen Pin 6 go higher but it's rare, this is also the case with both cables.

I have now undervolted my GPU to the point where HWiNFO shows the maximum A as no more than 9A when benchmarking Cyberpunk with path tracing, and the red LED on the GPU does not flash at all. (lost about 1-2% of FPS which in the grand scheme of things I do not mind for now)

I first of all want to know, is it safe to use my GPU right now with this undervolted setup until the issue is fixed.

Second, any tips on how to fix this issue? I have not used any adapters, only two different direct 12VHPWR cables, both of which belong to the same PSU!

[Silent_Scone]

Hi @sebbebro 

The LED will flash if one or more of the pins either exceed 9.2A or are at 0A. Technically, if the amperage is below 9.2A you're below the threshold for PowerDetector+ to flag an issue. However, you should inspect the cable if there is an imbalance on one or more of the pins - detecting issues such as this is the purpose of PowerDetector+ to avoid excessive heat through the cable / connector.

One pin at 3-4A whilst the others are around 8-9 is a huge imbalance. Inspect the connection at both the PSU and GPU end, and replace the cable if needed.

(P.S - fully agree with undervolting regardless - there's huge power savings there).

[sebbebro]

Thank you for the tips. However these are things I've tried with no difference in outcome.

I unplugged PC and then reseating cable was the first thing I did after seeing the red LED, and since that did not work I decided to inspect the cable. The normal pins looked completely normal but two of the sensor pins were a bit crooked. That was when I decided to try and switch to my other 12VHPWR cable which I inspected and looked perfectly normal. While the red light was less prominent it still lit up, and the imbalance was still there.

The cables did a distinct "click" noise when inserted both for the GPU and the PSU, so I'm pretty sure they're properly seated, I even applied a bit of extra force (not excessive though) after the click just to make sure.

For the record, the second cable uses the second 12VHPWR outlet on the PSU, so I've tried both of em.

I'm suspecting it might be a PSU issue but I want to see if there is anything else I can do first

[sebbebro]

Actually wait scratch that other reply, now I have a different issue. The opposite issue even.

I tried reseating both ends a 3rd time just to make sure. And well, I don't know what to say, it took a step in the right direction but way overshot. Pin 6 is no longer "lazy" but now it's the one getting all the work.

After reseating this time and trying to open Cyberpunk benchmark it shows pin 1 through 5 as using 7-8A while Pin 6 is constantly over 10A. I won't be trying to run any other benchmarks until I get a reply.

What happened here, suddenly the 6th pin has contact but now it seems like the other pins leave undone work to Pin 6

[Silent_Scone · Accepted solution]

Bad cable, look to replace it 

[sebbebro]

Ok so given that I have issues even after switching cables I guess both my cables happened to be faulty then. What luck I have, the chance for getting 2 bad cables at once can't be that high. I'll return to let you know once managed to get a new cable if it worked or not.

[Silent_Scone]

if the imbalance is changing which pin every time the cable is unplugged and plugged back in, it would indicate a cable of poor construction, yes

[sebbebro]

Alright thanks for your insight, so it's very unlikely to be the PSU or the GPU power connector then. I'll get a new cable as soon as I'm able!

[Silent_Scone]

far more likely to be the cable, yes

[sebbebro]

Hello I'm back now!
It took a while since I had warranty in a different country from where I live in order to get a new cable for my PSU but now I have managed to get one, I've been careful not to stress my PC during this time.

Now that I have tried the new cable it seems a lot better. The red light has not lit up yet even with benchmarking Cyberpunk with path tracing and maxed out settings. According to HWiNFO amps maxed out at 8.9A which I feel is a good sign.

I just want to double check if I'm in the clear now, my highest and lowest pin have a disparity of about 0.8-1A maximum (usually it hovers around 0.6-0.7A difference), is this considered normal? If it is then I can close this thread and I'll accept your answer as the solution!