Processor noise, specifically FPU noise

[saitamonje]

Hello everyone

I've recently build an APU A-10 5800k based pc, and it is making a strange noise since then, an almost constant buzzing, very very sharp noise, but not very loud, it's just annoying when I'm sitting at the pc.

I noticed that the noise would stop when I run Aida64 stress tests, and after that I noticed that I stops when I do the test setting on the "Stress FPU" checkbox. So, basically, I understand that the noise stops when the FPU (Floating-Point-Unit) is under heavy load. The noise also stops when I'm running games or doing other activities that involves heavy-processor load.

And I have to say that this problem has me a little nervous, should I care about it? Or is it normal?

PC Specs:

Asus A55bm-e FM2+
AMD APU A-10 5800k @stock + 7660 IGP @stock
Gskill 2133 Mhz 8GB 2x4 Gb 11-11-11-30
WD Blue Sata III 64Mb


Thanks in advance, and sorry for my english, it's not my mother language.

 

[i7Baby]

What is an FPU?

Maybe its an electronic whine? Is it fan noise? Stop the each fan for 1 sec and see if the noise stops.

 

[saitamonje]

Sorry, by FPU I mean Floating Point Unit, at least that's what Aida64 tests with that checkbox. I already tried the fan thing, even left the pc opened with no case fans to check that out, but the noise kept going on. I know it's not the cpu fan because the noise should get louder under heavy load, but the opposite thing happens.

So, I'm thinking it could be something related to the Floating Point Unit, but I don't know much about it

 

[Pinhedd]

It's probably just coil whine from the VRMs located near the socket. VRMs use programmable DC-DC step down converters known as buck converters. Buck converters contain an inductor which if not properly mounted may vibrate under certain current conditions

 

[InvalidError]

The FPU (Floating Point Unit) is the part of the CPU that deals with floating-point mathematics but this circuit operates at multiple GHz so it cannot generate any audible noise.

Whatever noise you are hearing must be coming from either your computer's power supply or local voltage regulators elsewhere such as the CPU VRM on the motherboard.

Since PWM regulators these days operate at over 200kHz, the noises you are hearing should be caused by a phase margin issue (lag) in the feedback loop making the regulator skip pulses. This is not necessarily harmful (need to hook up an oscilloscope and look at output's ripple to determine that) but it is certainly annoying.

 

[saitamonje]

It's probably just coil whine from the VRMs located near the socket. VRMs use programmable DC-DC step down converters known as buck converters. Buck converters contain an inductor which if not properly mounted may vibrate under certain current conditions

Thanks for the reply. Could there be a way to mount correctly that buck converter? I mean, is it something that I did wrong?

 

[i7Baby]

Did you test the fans?

If that makes no difference, then it's the electronics somewhere. And most likely 'coil whine'.

If its intermittent and not very loud, then I wouldn't worry about it.

 

[saitamonje]

Did you test the fans?

If that makes no difference, then it's the electronics somewhere. And most likely 'coil whine'.

If its intermittent and not very loud, then I wouldn't worry about it.

Yes its intermittent, and it's not loud but I hear it all the time, and its annoying :/

 

[i7Baby]

See if you can hunt down where the noise is coming from. Then decide whether you want to replace that bit. Is the cost worth the relief from the annoyance?

 

[saitamonje]

But is it possible to replace motherboard parts? I mean, if its the CPU VRM thats making the noise

 

[i7Baby]

The cpu doesn't have its own VRM. You'd have to replace the motherboard if thats where the noise was coming from.

 

[saitamonje]

I've just noticed something else. I started using my pc with Aida64 running stress test over the FPU only, so I don't hear the noise while browsing and stuff like that. And, the noise stops for a while after doing the stress test. It starts some time after, could it be something about temperatures?

 

[i7Baby]

Maybe. What temps you getting with aida stress test?

 

[saitamonje]

Up to 56º C. The most strange thing is that the noise stops at higher temps (if the temps are the cause)

 

[i7Baby]

56C is OK on a cpu stress test. Nothing unusual.

Where is the noise coming from?

 

[Zircoben]

Hello everyone

I've recently build an APU A-10 5800k based pc, and it is making a strange noise since then, an almost constant buzzing, very very sharp noise, but not very loud, it's just annoying when I'm sitting at the pc.

I noticed that the noise would stop when I run Aida64 stress tests, and after that I noticed that I stops when I do the test setting on the "Stress FPU" checkbox. So, basically, I understand that the noise stops when the FPU (Floating-Point-Unit) is under heavy load. The noise also stops when I'm running games or doing other activities that involves heavy-processor load.

And I have to say that this problem has me a little nervous, should I care about it? Or is it normal?

PC Specs:

Asus A55bm-e FM2+
AMD APU A-10 5800k @stock + 7660 IGP @stock
Gskill 2133 Mhz 8GB 2x4 Gb 11-11-11-30
WD Blue Sata III 64Mb


Thanks in advance, and sorry for my english, it's not my mother language.

I have the exact same CPU and RAM, and an FM2+ motherboard also.

I had some weird sounds, like a staticy buzz sound coming out of my speakers, and it would change with the load of the CPU. I changed my speakers to some Bose, and haven't heard it since.

Is it similar to that and does it come out of the speakers...?

Probably different problems, but hope that helps!

 

[saitamonje]

56C is OK on a cpu stress test. Nothing unusual.

Where is the noise coming from?

I can't know exactly, but its near the processor (or the processor itself). I'd say at the top of the socket, or at the sides, don't know which one. I know for sure its not from anywhere below the socket/processor because I've put my ear near every place in the case..

 

[saitamonje]

Hello everyone

I've recently build an APU A-10 5800k based pc, and it is making a strange noise since then, an almost constant buzzing, very very sharp noise, but not very loud, it's just annoying when I'm sitting at the pc.

I noticed that the noise would stop when I run Aida64 stress tests, and after that I noticed that I stops when I do the test setting on the "Stress FPU" checkbox. So, basically, I understand that the noise stops when the FPU (Floating-Point-Unit) is under heavy load. The noise also stops when I'm running games or doing other activities that involves heavy-processor load.

And I have to say that this problem has me a little nervous, should I care about it? Or is it normal?

PC Specs:

Asus A55bm-e FM2+
AMD APU A-10 5800k @stock + 7660 IGP @stock
Gskill 2133 Mhz 8GB 2x4 Gb 11-11-11-30
WD Blue Sata III 64Mb


Thanks in advance, and sorry for my english, it's not my mother language.

I have the exact same CPU and RAM, and an FM2+ motherboard also.

I had some weird sounds, like a staticy buzz sound coming out of my speakers, and it would change with the load of the CPU. I changed my speakers to some Bose, and haven't heard it since.

Is it similar to that and does it come out of the speakers...?

Probably different problems, but hope that helps!

Thanks for the reply, already tried that though, but the noise is there even with the speakers turned off and disconnected

 

[saitamonje]

There's another thing, the noise also starts when I use the mouse wheel or move windows around, could it be the IGP starting and stopping continuously?

BTW, thanks to everyone who has replied so far, you're being really helpful to me

 

[InvalidError]

There's another thing, the noise also starts when I use the mouse wheel or move windows around, could it be the IGP starting and stopping continuously?

If you are driving your display(s) from the IGP, the IGP is already active quite regularly to stream display output. Moving the mouse pointer would not add much activity on top of that.

If the CPU is mostly idle at the time though, the activity bursts from all the interrupts, context switches and other stuff involved in the whole update process might generate large enough power spikes to affect the VRM and cause a more distinctive whine pattern.

 

[i7Baby]

I have a feeling that the noise is coming from your motherboard. If you can verify that and decide its annoying you need t make the cesision whether to replace it.

Is the motherboard still in warranty?

 

[saitamonje]

I have a feeling that the noise is coming from your motherboard. If you can verify that and decide its annoying you need t make the cesision whether to replace it.

Is the motherboard still in warranty?

I have the same feeling. Yes it is, it still has a year warranty, I think I will leave it like that, perhaps some day the noise desappears, if not, I will send it to warranty later.

I still have to do a better cable management, perhaps disconnecting and reconnecting wires the noise disappears..

Anyway, thanks to everyone for your help!

 

[Pinhedd]

It's probably just coil whine from the VRMs located near the socket. VRMs use programmable DC-DC step down converters known as buck converters. Buck converters contain an inductor which if not properly mounted may vibrate under certain current conditions

Thanks for the reply. Could there be a way to mount correctly that buck converter? I mean, is it something that I did wrong?

I have a feeling that the noise is coming from your motherboard. If you can verify that and decide its annoying you need t make the cesision whether to replace it.

Is the motherboard still in warranty?

I have the same feeling. Yes it is, it still has a year warranty, I think I will leave it like that, perhaps some day the noise desappears, if not, I will send it to warranty later.

I still have to do a better cable management, perhaps disconnecting and reconnecting wires the noise disappears..

Anyway, thanks to everyone for your help!

Check the inductors to the immediate left of your CPU socket. These are labelled R68 on your motherboard (going by the diagram on Asus's website) and are responsible for stepping down the FET modulated 12 volt supply rail to a more desirable level without burning the excess power off as heat (they store it in a magnetic field instead).

 

[saitamonje]

It's probably just coil whine from the VRMs located near the socket. VRMs use programmable DC-DC step down converters known as buck converters. Buck converters contain an inductor which if not properly mounted may vibrate under certain current conditions

Thanks for the reply. Could there be a way to mount correctly that buck converter? I mean, is it something that I did wrong?

I have a feeling that the noise is coming from your motherboard. If you can verify that and decide its annoying you need t make the cesision whether to replace it.

Is the motherboard still in warranty?

I have the same feeling. Yes it is, it still has a year warranty, I think I will leave it like that, perhaps some day the noise desappears, if not, I will send it to warranty later.

I still have to do a better cable management, perhaps disconnecting and reconnecting wires the noise disappears..

Anyway, thanks to everyone for your help!

Check the inductors to the immediate left of your CPU socket. These are labelled R68 on your motherboard (going by the diagram on Asus's website) and are responsible for stepping down the FET modulated 12 volt supply rail to a more desirable level without burning the excess power off as heat (they store it in a magnetic field instead).

Thanks for the reply. What should I be checking, temperatures?

 

[InvalidError]

Thanks for the reply. What should I be checking, temperatures?

Take a paper towel's cardboard core, stick one end on whatever the suspected noise source is and stick your ear on the other end. When the "business end" of the tube is on the correct component, you should be getting the loudest sound.