Question My psu is making weird static noise

Aug 10, 2019
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I have a brand new cx750m that's only a month old but recently I noticed at high load, or when the fan is actually spinning higher, i can hear a slight weird static noise coming from the psu. It only occurs when the fan is spinning at a certain rpm I guess because I dont hear it at lighter loads. I'm not sure if this has just started occurring because I've really only went to the back of my pc and checked it last night.

Is this normal noise or possibly something wrong with my fan?
 

Darkbreeze

Titan
Moderator
Sounds like a problem with the fan bearing although it's hard to say without actually being there to hear it. Doesn't really matter though, it shouldn't be making noise. Contact Corsair and get an RMA started. It should be replaced no matter what if it is making noises or behaving in any way outside the normal parameters for a correctly functioning power supply.
 

jonnyguru

Distinguished
I have a brand new cx750m that's only a month old but recently I noticed at high load, or when the fan is actually spinning higher, i can hear a slight weird static noise coming from the psu. It only occurs when the fan is spinning at a certain rpm I guess because I dont hear it at lighter loads. I'm not sure if this has just started occurring because I've really only went to the back of my pc and checked it last night.

Is this normal noise or possibly something wrong with my fan?
What graphics card are you using? That PSU has a double forward topology and some higher end graphics cards will have transient loads during games or benchmarks that will cause the main transformer to make a buzzing noise.

Sounds like a problem with the fan bearing although it's hard to say without actually being there to hear it. Doesn't really matter though, it shouldn't be making noise. Contact Corsair and get an RMA started. It should be replaced no matter what if it is making noises or behaving in any way outside the normal parameters for a correctly functioning power supply.
So he can get a replacement that does the same thing? Could just be magnetic noise (aka: coil whine) coming from a coil, X cap, transformer, etc.

He can tell if it's the fan by just stopping the fan to see if the noise coincides with it.
 
Aug 10, 2019
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What graphics card are you using? That PSU has a double forward topology and some higher end graphics cards will have transient loads during games or benchmarks that will cause the main transformer to make a buzzing noise.



So he can get a replacement that does the same thing? Could just be magnetic noise (aka: coil whine) coming from a coil, X cap, transformer, etc.

He can tell if it's the fan by just stopping the fan to see if the noise coincides with it.
I'm using a rtx 2070 super founders edition. It seems like my psu is working harder in some games as well.. when I run destiny 2 it only really revs up and gets louder at some instances but for the most part it's pretty calm. Gears of war 5 for instance seems to run my psu louder, along with my gpu temps. I rarely ever run above 70 c on my gpu but gears 5 seems to.
 
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jonnyguru

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I'm using a rtx 2070 super founders edition. It seems like my psu is working harder in some games as well.. when I run destiny 2 it only really revs up and gets louder at some instances but for the most part it's pretty calm. Gears of war 5 for instance seems to run my psu louder, along with my gpu temps. I rarely ever run above 70 c on my gpu but gears 5 seems to.
Where did you buy the PSU from and how long ago?
 
Aug 10, 2019
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It seems
Where did you buy the PSU from and how long ago?
The psu is brand new and it's only a month old. I bought it from best buy. It's not the old cx750m with the green label, it's the new grey label. I only hear this slight staticky sound when the fan is really being worked, not at all times. I have to put my ear to the back of my pc to really even hear it..
 

jonnyguru

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It seems

The psu is brand new and it's only a month old. I bought it from best buy. It's not the old cx750m with the green label, it's the new grey label. I only hear this slight staticky sound when the fan is really being worked, not at all times. I have to put my ear to the back of my pc to really even hear it..
Right. But if you stop the fan, does it still make the noise? I'm trying to figure out if the noise is the fan (which would be a defective unit) or the main transformer (which would be normal, but if it bothers you you can return the PSU and get something more appropriate for your build since the CX-M is a "budget" PSU and a RTX 2070 is not a "budget" graphics card).

Cards like 2070's, 2080's, etc. can be hard on the main transformers of double forward topology PSUs causing them to buzz. If you don't want the noise, you should get a better PSU that uses an LLC resonant mode front end, like the CX (non-M), TX-M or higher.

Doesn't matter if it's green label, gray label, etc. There was only one version of the CX750M:

http://www.jonnyguru.com/forums/showthread.php?16610-Corsair-CX-and-CX-M-quot-cheat-sheet-quot
 
Aug 10, 2019
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Right. But if you stop the fan, does it still make the noise? I'm trying to figure out if the noise is the fan (which would be a defective unit) or the main transformer (which would be normal, but if it bothers you you can return the PSU and get something more appropriate for your build since the CX-M is a "budget" PSU and a RTX 2070 is not a "budget" graphics card).

Cards like 2070's, 2080's, etc. can be hard on the main transformers of double forward topology PSUs causing them to buzz. If you don't want the noise, you should get a better PSU that uses an LLC resonant mode front end, like the CX (non-M), TX-M or higher.

Doesn't matter if it's green label, gray label, etc. There was only one version of the CX750M:

http://www.jonnyguru.com/forums/showthread.php?16610-Corsair-CX-and-CX-M-quot-cheat-sheet-quot
What's the best way to stop the fan and test it? Do I need to physically open up the back of my pc and stop the fan myself? And if it is the transformer making that noise, which you say is normal with my unit and gpu, is that going to hurt anything in my PC? That's my main concern right now, I just dont want it to hurt any other components because of it for the time being until I switch my psu to a better one.

I have done research and realized my cx750m wasnt the best choice for my build, and I plan on upgrading in the future to a better quality psu but I cannot afford to do it at this time.
 

jonnyguru

Distinguished
What's the best way to stop the fan and test it? Do I need to physically open up the back of my pc and stop the fan myself? And if it is the transformer making that noise, which you say is normal with my unit and gpu, is that going to hurt anything in my PC? That's my main concern right now, I just dont want it to hurt any other components because of it for the time being until I switch my psu to a better one.

I have done research and realized my cx750m wasnt the best choice for my build, and I plan on upgrading in the future to a better quality psu but I cannot afford to do it at this time.
Don't open the PSU or anything. Just take a pencil eraser or Q-tip and stick it on the hub of the fan and slow it down until it stops while you listen to the PSU. That's all. If the pitch of the buzz doesn't change with the speed of the fan, then it's the main transformer.

I asked when and where you bought it from because it's probably pretty easy for you to walk into Best Buy and return it for a full refund. Best Buy's pretty good with their returns.

If you have $20 more, bring the CX750M back and get the RM750.

But if you don't have $20 to spare, the good news is YOU DON'T NEED 750W!!!

Unfortunately, Best Buy doesn't have much of a selection. So if you can get your money back, you should order a CX650 (non M) or RM650 from Amazon or Newegg instead and actually SAVE $20 instead!!
 
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Yanitwei

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Dec 7, 2016
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I think it is a phenomenon called coil whining
View: https://www.youtube.com/watch?v=M7joy0eh1RM
View: https://youtu.be/T7HsXHqtxrI?t=55


it's happening when PSU is under load, mine is also doing same thing

That's a common issue, almost all 80 plus BRONZE certified PSUs are suffering from coil whining, If you cant RMA it, just live with that there's nothing you can do, use V-sync, try to control it's power consumption, some games opened in window mode might cause higher GPU load so GPU will take more power from PSU and PSU will start whining.
 
Aug 10, 2019
76
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I think it is a phenomenon called coil whining
View: https://www.youtube.com/watch?v=M7joy0eh1RM
View: https://youtu.be/T7HsXHqtxrI?t=55


it's happening when PSU is under load, mine is also doing same thing

That's a common issue, almost all 80 plus BRONZE certified PSUs are suffering from coil whining, If you cant RMA it, just live with that there's nothing you can do, use V-sync, try to control it's power consumption, some games opened in window mode might cause higher GPU load so GPU will take more power from PSU and PSU will start whining.
Yeah it sounds like that's what it is. It only happens when the gpu/psu is under more load. I haven't done the fan testing yet but from the sounds of it it seems like it is the transformer making that noise. I will eventually replace the psu with a better one but am I ok for right now? I just dont want to make sure it will not affect my gpu or any other component in my system
 

Yanitwei

Commendable
Dec 7, 2016
38
0
1,540
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I will eventually replace the psu with a better one but am I ok for right now? I just dont want to make sure it will not affect my gpu or any other component in my system
You are totally OK it won't harm any component of your PC, you can be calm about it. It just makes that noisy sound under loads and that's it, nothing else.
 

Yanitwei

Commendable
Dec 7, 2016
38
0
1,540
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Glad you are so sure of that, without having done anything to hear, test or otherwise determine that. Guess we can all go home now.
Yea I'm using same PSU for almost a year now, When I heard that sound for the first time I was also confused, I made a lot of research in internet as well, went through all possible ways to go so I know for 100% sure. I'll handle this and you can go home.
 

Darkbreeze

Titan
Moderator
And, that's totally not true either, much as JonnyGuru has already alluded to. It's mainly a problem on the platforms using double forward designs. It is much less prevalent, or nonexistent, on those using LLC resonance.

And, just in case you were unaware, JonnyGuru, above, is pretty knowledgeable when it comes to power supplies. FAR, FAR more so than you or I. It doesn't mean I always agree with him, but I don't argue when it comes to something specific and technical like this, because you'll lose every time.

https://www.corsair.com/us/en/blog/rb_jg_interview
 

Darkbreeze

Titan
Moderator
I doubt it. It's not a matter of finding out the issue. It's a matter of the problem being directly linked to the design of the platform, and topology, which nobody is going to worry too much about trying to fix when there are already designs that don't do that but at a higher price point. If you want a budget product, you tend to get budget results. People should start expecting that when they go cheap instead of expecting to be able to go cheap and still get the same results as people who are willing to pay more.
 

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