Weird buzzing noise from GPU

[Snorlaxxx]

Hey,

I finally got my ek backplate for my 290 DCU II.
The GPU is running for a few weeks now, watercooled with an EK full block.
Nice temps and quiet.

Today I installed the backplate, took the six screws and washers out, put the plate with the thermal pads on it on the GPU and fixed it with six new screws (no washers).
At first everything seemed fine. I mean, it's just a simple thing...
But I was greatly mistaken. As soon as I taxed the GPU with a game or benchmark the card made some sort of a buzzing sound. This is not your typical high pitch coil whine, but sounds rather like a loud cheap fan with a nasty motor rattle. It is really loud and annoying.

I let it run for quite some hours, hoping it would settle, but it didn't.
After checking a little more, I discovered that the sound came from the rear end of the card. The area where the thermal pad on the backplate is.
Loosening the screws a little and "pulling" the backplate up decreased the intensity and made it almost stop.

My guess is the coil whine the card would have made resonates through the TIM into the backplate, causing the whole thing to get amplified.

I googled this, but nobody seems to have this problem.


Any ideas?

How about running the backplate without thermal pads? Temps are fine as they are even without the plate. Or would the heat be trapped under the plate, causing the card to overheat?

 

[RnRollie]

if its coil whine, setting it to run furmark for a few hours should settle it... if it doesn't blow the VRMs up.

i'ld reseat the backplate first.. see if every pad is indeed making contact

 

[Snorlaxxx]

This is soooo rediculous... Just removed the backplate again and trimmed the thermal pad a little more. Contact points are clearly visible and that's just the thing.
It only makes a sound when it has pressure on it, i.e. is screwed on.
Right now I have it just lying there on top of the GPU and the noise is minimal to none.
As soon as I put pressure or even touch the backplate the buzzing starts.


I don't know what else I can do to solve this

 

[GTXJackBauer]

That nuts. I would contact EK and see if they have a solution. I am sure they've done their tests that can assist you.

 

[EarthDog]

I'm guessing the tension the backplate is putting on the pcb is causing a slight warping in the pcb which is affecting the coils.trimming thermal pads, assuming this is coil whine won't help... Unless somehow that changes the tension, but... Not sold it would be enough.

 

[Snorlaxxx]

I'm guessing the tension the backplate is putting on the pcb is causing a slight warping in the pcb which is affecting the coils

That's what I thought, too, when I tried lifting and pressing the backplate.
I saw a slight bend towards the end of the card. But I don't thinkt that's the source of the problem. The noise wasn't only present when the backplate was screwed on thight, maybe caused by bending, but it was there as soon as I put a finger on it. So it has to be some kind of an amplification / resonate problem. idk.

For now I removed the VRM thermal pads and the noise is gone.

Temp wise I don't see a huge different, if any at all. I didn't do ultra scientific tests, but a quick look at the Aquaero sensor graphs during benching and gaming show about the same temps for the GPU and VRM1.


Still a very strange thing


Maybe this can be of some help to anybody encountering a similar problem.
If I hadn't mounted the backplate afterwards, but assembled everything at once, I would have thought my card has terrible coil whine. Of course that would have meant to take the whole loop apart and RMA the card.

TLR
If your watercooled GPU buzzes, check your backplate.

 

[GTXJackBauer]

Great find Snorl.

 

[EarthDog]

Wait a sec? What card has VRM's on the back of it?

 

[BruceUSA]

You should not be removing the thermal pad, as it suppose to be there to help cool the card efficiently under loads.

 

[Daddyjaxx]

Wait a sec? What card has VRM's on the back of it?

A lot apparently do, but that doesn't mean they need any additional cooling. If you look at this link for a 780TI, it specifically says VRM's on the back.

http://www.frozencpu.com/products/2..._Backplate_-_Black_Rev20.html?tl=g57c613s1932

 

[EarthDog]

That is a 780 not a Ti... and I also do not read it that way, but can see the source of confusion in that wording.

There are no VRM's on the back of a 780 Classy. It is providing passive cooling for them on the back side, I would imagine, via thermal pads as the PCB does certainly soak up a lot of their heat. But like I said, those are typically found on the front of the card. If you come across a card with them on the rear, link me up.

I just think that statement was misunderstood. The GTX 295 backplate says the same thing and there are no VRM's on its backside. If the card never came with one and it was not cooled, I would say not using the thermal tape is fine. However if there was a backplate and it used the tape before, I wouldn't remove it.

 

[bamato]

Perhaps the backplate should have been mounted before the waterblock? Uneven stress on the card or something?

 

[Daddyjaxx]

You have to mount the blocks first. The back plates are for specific blocks. Generally, you have to remove some of the water block screws, install the back plate, and replace the screws with different longer screws.

 

[bamato]

^^Whoops. Thanks for that correction. Over-tightened the block maybe?