Question Ground loop noise with 4090 FE?

[Xtrattitude4u]

I just built a new gaming PC and have a really loud buzz coming from my AVR powered speakers.

System:
Fractal Torrent
MSI PRO z690a
Intel 12600k
Corsair Rm850x
4090 FE

I've had this issue before, but after upgrading to the 4090 FE, The problem is much much worse.

This buzzing increases in volume with GPU load. when I'm running a benchmark or playing a demanding game, it gets really really loud. based on this, it seems to me it's really the GPU having a lack of ground, but perhaps my logic is flawed.

I have HDMI from 4090 FE going to an AVR, and another HDMI to my TV.

I have an analog RCA from AVR to my subwoofer amplifier. If I disconnect the the HDMI cable or the RCA cable, the noise is gone.

so it appears the GPU is finding ground through the HDMI / RCA, thus going through the analog portion of the receiver and causing the noise. The PC and the amplifier are the only two grounded components in my home theater, so it makes sense.

Both have their power connectors plugged into a Furman power conditioner / surge protector. but I also had the same issue when they were just plugged into the wall, and on a completely different surge protector.

The only way I've been able to help this is to make a ground strap and connect it between one of the mounting screws on the GPU, and a ground screw on the amplifier, bypassing the reciever.
Doing the same between the receiver case and the amplifier case helps as well.

This helps, but doesn't solve the problem completely.

So it appears I have a lack of ground with the GPU somehow. I had this problem with my 1060 in the same computer, but got way worse when I upgraded to the 4090.

I also had this problem with a completely different PC.

I've tried both the standard 4090 power adapter with the PSU cables, as well as Corsair's single power adapter solution, and the problem seems identical.

This problem all started when I added a grounded amplifier for my subwoofer, but I have never had a grounded subwoofer or amp before.

What I don't understand, is why the GPU is not finding a better ground through the PSU which is grounded. I would think that would be a much easier, better path to ground then through the HDMI cable, receiver, audio stack, RCA.

I know there are filters available, and the ground strap is helping, but I just can't understand why this problem is happening in the first place.

Are these GPUs just not properly grounded to their own power connector?

 

[drivinfast247]

Odds are there's a problem with your receiver. Try connecting the GPU directly to the TV via HDMI. See if the noise is gone.

 

[Xtrattitude4u]

Odds are there's a problem with your receiver. Try connecting the GPU directly to the TV via HDMI. See if the noise is gone.

While I agree that would fix the problem, it wouldn't be because there's a problem with the receiver. The TV isn't grounded, so there would be no other path to ground. This is also a brand new receiver and I've had the same issue with the previous one.

 

[drivinfast247]

You stated you had the problem with 2 PCs, and two different GPU. Not sure how you came to the conclusion of the 4090 being the culprit.

Remove the audio cable from the subwoofer. What happens?

 

[Xtrattitude4u]

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Yes the sound goes away if I unplug the Subwoofer amplifier.
I think the problem is the pro amp I'm using, which I found many users have complained about, due to noisy RCAs.

I think that amplifier (Crown XLS2502) has a strong path to ground through its RCAs, which the video card ends up partially grounding through.

The ground strap connected between the 4090 and the amplifier reduces the noise enough to where I can't hear it from the seating position, so I'll live with that.