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.

 

[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).

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

Check it for audible noise. As InvalidError suggested, use a narrow tube or something to focus on one component at a time.

 

[saitamonje]

I checked with a paper tube to find some noise, but didn't find the exact place. What I've noticed is that now, with Aida stress test, the noise stops also when I check the CPU, FPU, Cache and System memory boxes, with any of those boxes checked the noise also stops. I'm starting to think perhaps it could be something about the processor, am I right?

And now that I'm thinking, I remember that when I installed the CPU cooler (or fan), once I had it placed and secured, I tried to move it a little upwards, maybe 1 mm as much, because I felt it was not centered (I know it sounds stupid, now I realize).. Could that have something to do with the noise?

 

[i7Baby]

Check whether the latch is still closed on the cpu and whether the cooler is still attached firmly

 

[saitamonje]

Check whether the latch is still closed on the cpu and whether the cooler is still attached firmly

Yes, it's still very firm. If I remove the cpu cooler, the thermal paste could suffer any "damages"? I mean, can I remove the cooler and put it again in its place just like that or do I have to replace the thermal paste?

 

[i7Baby]

Don't remove the cooler

 

[saitamonje]

Don't remove the cooler

I didn't mean removing the cooler like throwing it away, I meant to get it out and put it back, perhaps that could help.. Could that be harmful?

 

[InvalidError]

I didn't mean removing the cooler like throwing it away, I meant to get it out and put it back, perhaps that could help.. Could that be harmful?

Whacking the HSF off and putting it back on as-is introduces large air bubbles in the paste which can significantly degrade heat transfer.

 

[saitamonje]

There's another thing now, when the pc is idle the noise is an intermittent clicking, like a little tiny piece of metal pounding another one. And when I keep down a key, the noise repeats for each letter that I write. If, for example I write DDDDD, the noise repeats five times. I can hear it from 3-4 meters away from the case (10-12 ft). Does that say something else?

Thanks for all the help so far!!

 

[InvalidError]

There's another thing now, when the pc is idle the noise is an intermittent clicking, like a little tiny piece of metal pounding another one.

The few times I have had coil whine that seemed related to user events, I would compare the sound to something like small glass marbles hitting each other.

Well, since you did not find the noise around the CPU, you should try the computer's PSU. Inductors and transformers are pretty much the only things that can directly convert electrical noise into significant amounts of audible noise short of sticking a speaker or other transducer in there.

 

[saitamonje]

Sorry for the late response. I finally found that the noise was coming from the PSU, not anywhere else. I found this out when I got the PSU out of the case and checked it that way (my case has the PSU space in the top, that's why I confused the noise with the cpu or mobo). Sorry for not checking this out earlier.. Anyways, I'm sending it to the reseller under the guarantee. I've found on the net that it's not dangerous for the PSU to make that noise, but it is really annoying.

Thanks everyone for the help, because you've been really helpful

Greetings

 

[Pinhedd]

Sorry for the late response. I finally found that the noise was coming from the PSU, not anywhere else. I found this out when I got the PSU out of the case and checked it that way (my case has the PSU space in the top, that's why I confused the noise with the cpu or mobo). Sorry for not checking this out earlier.. Anyways, I'm sending it to the reseller under the guarantee. I've found on the net that it's not dangerous for the PSU to make that noise, but it is really annoying.

Thanks everyone for the help, because you've been really helpful

Greetings

Glad you got it figured out

 

[InvalidError]

I've found on the net that it's not dangerous for the PSU to make that noise, but it is really annoying.

That depends on the exact reason why it is whining.

If it is a phase margin thing like I mentioned in my first post or intermittent operation due to low load (PWM starts, voltages overshoot, PWM stops, voltages drop, PWM starts again, rinse and repeat), some components might not like the extra ripple and noise this may generate.

If the noise is simply caused by change in magnetic mechanical loading (vibrations) related to load changes then yes, the noise is completely harmless.