Mac Pro 2012 Random “Snap” Sound

[Nanco]

Hi there,

I know its probably a long shot, but I thought I’d create this post just in case anyone might be able to help shed any light on this situation or if perhaps anyone else has come across this same problem before.

For a few months now my Mac Pro has been producing a random snapping sound. It can sometimes occur just once or multiple times a day and isn’t triggered by a specific thing. It is a one time “snap” and isn’t like a sequence of snaps in a row if that makes sense. Its not necessarily a loud snap, but I’d consider it louder than HDD clicking. If I had to guess, I think the problem might have started after an internal clean a few months ago with a vacuum cleaner and compressed air (the same way I’ve cleaned this and many other systems throughout my entire life so far, so would be very surprised if this has caused the issue).

The operation of the Mac is as good as its ever been so I can’t see any degradation in performance, increase in random kernel panics (I can’t remember when I had one last) or anything that would clearly suggest there is something actually wrong.

I have completely removed the drive bays (including super drives) and have gone as far as purchasing a brand new SSD to rule out possible signs of HDD failure to no avail. I have tried altering the fan speeds to see if that helps to identify any issues but this has not influenced the snapping sound in any way. I have gutted the PC and cleaned the components from top to bottom to rule out dirt and dust and I could not identify anything on any of the boards that might suggest damage. Besides the replacement SSD mentioned as a means of troubleshooting, there have been no other hardware changes since originally purchasing the Mac in 2012.

For the next step, I’m trying a different power cable plugged into a different outlet for a few days to see if that rules out possible power issues.

Though the next step might involve sticking a microphone in the case to try and locate the snap, I am actually at a loss for what to do next. I’m not 100% sure on this, but the snap appears to emanate from the front of the Mac.

I appreciate any help I can get at this point.

Kind Regards,
Matt

 

[rachalmers]

Hi there,

I know its probably a long shot, but I thought I’d create this post just in case anyone might be able to help shed any light on this situation or if perhaps anyone else has come across this same problem before.

For a few months now my Mac Pro has been producing a random snapping sound. It can sometimes occur just once or multiple times a day and isn’t triggered by a specific thing. It is a one time “snap” and isn’t like a sequence of snaps in a row if that makes sense. Its not necessarily a loud snap, but I’d consider it louder than HDD clicking. If I had to guess, I think the problem might have started after an internal clean a few months ago with a vacuum cleaner and compressed air (the same way I’ve cleaned this and many other systems throughout my entire life so far, so would be very surprised if this has caused the issue).

The operation of the Mac is as good as its ever been so I can’t see any degradation in performance, increase in random kernel panics (I can’t remember when I had one last) or anything that would clearly suggest there is something actually wrong.

I have completely removed the drive bays (including super drives) and have gone as far as purchasing a brand new SSD to rule out possible signs of HDD failure to no avail. I have tried altering the fan speeds to see if that helps to identify any issues but this has not influenced the snapping sound in any way. I have gutted the PC and cleaned the components from top to bottom to rule out dirt and dust and I could not identify anything on any of the boards that might suggest damage. Besides the replacement SSD mentioned as a means of troubleshooting, there have been no other hardware changes since originally purchasing the Mac in 2012.

For the next step, I’m trying a different power cable plugged into a different outlet for a few days to see if that rules out possible power issues.

Though the next step might involve sticking a microphone in the case to try and locate the snap, I am actually at a loss for what to do next. I’m not 100% sure on this, but the snap appears to emanate from the front of the Mac.

I appreciate any help I can get at this point.

Kind Regards,
Matt

I know this. It’s the hard drive parking. Some drives have built in sleep mode on the drive. It’s not to do with the computer, just the drive.
Now. When the drive wakes up... it proceeds, but when parking again... snap.
I’m not sure if it’s damaging the drive and you can get a bit of software that stops it. Overrides the drive code.
It’s a ‘feature’ of some drives. Not all.
I got rid of mine in the end. Didn’t want a failed drive in the middle of something

But... with no hdd, it sounds like a capacitor discharge. And they are not just on the main board, but the power supply is the main culprit.


Sent from my iPhone using Mac-Forums

 

[pigoo3]

Two thoughts:

1. Could be the beginning of the power supply going bad (partial failure)...but usually you don't hear that many "SNAPS" before a PS dies...usually it's one BIG POP...followed by some stinky smoke.
2. Here's a crazy idea...maybe your Mac Pro is acting like a bug-zapper.

Maybe the occasional bug (spider, moth, fly, ant, mosquito, etc.) is getting in there...finding something highly charged...and getting ZAPPED!

- Nick

 

[rachalmers]

Hmm. So what else is on the same power circuit as the Mac? A fridge, stove, aircon or something else that’s switching on/off. A cloths iron?
Something that’s developed arcing in its switching. The resulting arc surge will be heard in the speaker as the EMF hits it.
and won’t do your Mac any good either.
Doesn’t even have to be the same plug, just near enough is all it needs.



Sent from my iPad using Mac-Forums

 

[Nanco]

But... with no hdd, it sounds like a capacitor discharge. And they are not just on the main board, but the power supply is the main culprit.

I actually had the power supply open just a couple of days ago and didn’t notice any bulging capacitors or points of interest. I haven’t heard any sounds coming from the power supply itself, though I could swap it with the one from my backup system for a few days to help with troubleshooting. Thanks for the suggestion!

Here's a crazy idea...maybe your Mac Pro is acting like a bug-zapper.

Haha! If that is the case, then the poor victims are incredibly courteous as not to make a mess inside my computer. Unless they’re disintegrated on impact then I don’t think this is the cause sadly. Great suggestion though!

So what else is on the same power circuit as the Mac?

The Mac is usually plugged into a power strip that is shared with some of my outboard gear, preamps, speakers etc. This strip is then plugged into the outlet.

My area is audio engineering so I have to be attentive to noise isolation and ensuring my gear is properly powered at all times. I haven’t noticed any interference in other gear that shares this power strip, however as of today I have bypassed that altogether and plugged the Mac directly into the outlet with a different power cable. So far, so good (touch wood) but it is still early days. I’ll only know for sure after a few days if this really has narrowed the problem down.

As for interference from other appliances in the building, I cannot say for sure without doing a full audit. As far as I’m aware, there are no other things interfering with the electrics right now as it would most likely be audible through the speakers first.

 

[pigoo3]

The Mac is usually plugged into a power strip that is shared with some of my outboard gear, preamps, speakers etc. This strip is then plugged into the outlet.

My area is audio engineering so I have to be attentive to noise isolation and ensuring my gear is properly powered at all times. I haven’t noticed any interference in other gear that shares this power strip, however as of today I have bypassed that altogether and plugged the Mac directly into the outlet with a different power cable. So far, so good (touch wood) but it is still early days. I’ll only know for sure after a few days if this really has narrowed the problem down.

Is it possible the snap or pop is coming thru the Mac Pro's speaker...in reaction to something to do with your audio equipment...or like member rachaimers mentioned, something electrical on the same circuit (and coming thru the Mac Pro's speaker)?

- Nick

 

[Nanco]

Is it possible the snap or pop is coming thru the Mac Pro's speaker...in reaction to something to do with your audio equipment...or like member rachaimers mentioned, something electrical on the same circuit (and coming thru the Mac Pro's speaker)?

- Nick

The sound is handled by an Apogee Ensemble interface via firewire which then sends the audio to my external speaker set up. This is the default I/O device so the internal Mac speaker is not actually used besides for the startup chime.

After isolating the Mac from the power strip yesterday, all was well until about midnight when I had two snaps within the space of about 10 minutes of each other. Nobody else was around at that time and no other electrical appliances were in use in the building to my knowledge.

Today I’ve gone one step further and basically unplugged everything apart from the essentials (mouse, keyboard, one screen) and I’m also powering the screen independently from my outboard equipment. The main outboard power cable is unplugged and the switch turned off. Within the first maybe 10 minutes of the machine being turned on, I had about two or three snaps.

I’m not completely ruling it out, but I’m not entirely convinced that the problem is anything to do with what is going on outside of the Mac at this stage. The next thing I’m probably going to do is inspect the fans including the graphics cards and maybe try disconnecting one at a time to see if that helps to locate the snapping source.

I don’t know if its at all possible to give an accurate answer, but how long should I leave the Mac turned on with one of its fans removed? Obviously temperatures will be affected, but considering the random nature of this snap, I’m not sure that I would want to have a fan removed all day waiting for the snap to occur if there is sign of it damaging the computer in any way.

On a side note, the power supply fan appears to be emitting a low whirring sound (the pitch is roughly 40hz at around 600-650 RPM). Funnily enough I don’t recall this fan being so noticeable even when idle and under no major load (I've just lived with it for a while). Could this be linked with my problem or just something entirely different? Is it worth investing in a replacement?

Thank you both for your help so far. I'm determined to get to the bottom of this.

 

[pigoo3]

The sound is handled by an Apogee Ensemble interface via firewire which then sends the audio to my external speaker set up. This is the default I/O device so the internal Mac speaker is not actually used besides for the startup chime.

I only mentioned the "Mac Pro's speaker" since I didn't 100% know if you had external speakers connected. My point was...could the snapping/popping noise be coming thru whatever speaker is being used by your Mac Pro...due to some sort of electrical surge/noise on the home wiring. Sounds like you're saying no.

I don’t know if its at all possible to give an accurate answer, but how long should I leave the Mac turned on with one of its fans removed? Obviously temperatures will be affected...

I wouldn't fool around with the computers cooling system. Finding out the source of the snapping/popping isn't worth possibly damaging the computer (bad return on investment).

I would stick to more traditional & creative ways to try to troubleshoot & isolate things. I think disconnecting everything external is a great start...and personally I would pay close attention to the power supply area for the snapping/popping sounds.

But of course trying to more closely isolate where the popping/snapping is coming from is the most important...since that will allow to to focus much more on a specific area of the computer...and only consider the parts in that area that might be making the sound.

I don't know where you have your Mac Pro located. But if it's on the floor next to you...might be better to place it on your desktop...or on a chair or table right next to you (same height)...so when the sound happens...when you hear it...you can better determine what part of the Mac Pro case the sound is coming from.

- Nick

 

[rachalmers]

Interesting problem. Lets see. Do you still get the sound if the computer is somewhere else? I mean, unless you live in a one room apartment. Put it in another room.
Is there any ozone smell generated with the snap? (Electrical)
How loud is it? You can hear it across the Room? Across the street?
A wireless transmitter near you? Ham radio type thingy. They can cause mayhem if the antenna isn’t tuned properly. I once had a bare speaker sitting on a window sill not connected to anything, and the neighbours ham radio transmissions were coming through it, until I told him.
Which is why I mentioned it a few posts back. A speaker doesn’t have to be connected to anything to be able to pick up emf, if it’s a traditional moving coil speaker. Piezo of course doesn’t do it. Your audio equipment won’t pick up that stuff because it’s almost certainly shielded and earthed perhaps. I don’t think I’ve ever seen a computer with shielding.
Do you have it plugged into a surge protector? Even better a battery standby. A UP, an uninterruptible power supply.
Let’s face it, the only thing that can create a snap like you describe is metal moving. Expansion/contraction, or something electrical discharging. If your speaker is disconnected will you hear it. If so... it’s one of those two. The case or some part of it heating up and snapping as it cracks into place, or something arcing. In which case you will smell the ozone. Unless you are a smoker then of course you’ll be lucky to smell anything!



Sent from my iPad using Mac-Forums

 

[Nanco]

I don't know where you have your Mac Pro located. But if it's on the floor next to you...might be better to place it on your desktop...or on a chair or table right next to you (same height)...so when the sound happens...when you hear it...you can better determine what part of the Mac Pro case the sound is coming from.

I’ve done this now and I fear it might have raised more questions than solutions. That said, my Mac has been good for the past 24 hours and I have only had one instance of the snap which I think is actually coming from the graphics card (possibly the fan?). I noticed when I loaded a game that the fan began to speed up and its almost as if the snap occurred at each stage of the fan speeding up. When it reached a consistent speed, I didn’t hear any further snaps.

I’ll be keeping an eye on things over the weekend and will post if I notice this snap coming from anywhere else in the Mac. With what I noticed so far, I can confidently say that I didn’t notice anything visual to accompany the snap like arcing or lights.

I do have some further questions about the graphics card/s in my Mac, however I might create a separate thread for that later as not to go too far off topic. I did notice some things about the power supply and the fan (I mentioned the latter in my last post).

Interesting problem. Lets see. (snip)

I have a Mac Pro 2008 model that I use as a backup and for extra storage. I’ve since learned that I can’t simply swap out the power supply from this Mac to my 2012 one, however one thing I noticed was just how quiet the actual power supply was in comparison to the one in my 2012 Mac Pro. Here is a short video to hopefully better explain the sounds coming from the fan and the back of the power supply:

PSU Fan Hum and PSU Buzz.mp4 - Google Drive

I swapped the power plug from the 2008 Mac and plugged it into my 2012 Mac (same outlet and same plug with nothing else external plugged into the mac). The 2012 power supply was still quite noisy. I also tried plugging into a surge protector strip and Furman power conditioner, neither of which affected the noise.

The higher pitched noise is not as noticeable when the Mac is under my desk, however I’m actually curious if this sound is considered normal or if its the sign of a failing power supply. It doesn’t appear to be interfering with my outboard equipment, so I can only assume this sound is isolated to the Mac and is not caused by anything external (especially considering my other Mac is silent in comparison). I also have no idea how long this noise has been present as it is drowned quite well under the desk and especially with whatever is coming through my speakers drowning it even further.

I haven’t experienced any other signs of possible power supply failure, however what do you think? I have not noticed any smells coming from the Mac or around the power supply area (non-smoker, my sense of smell is very good. I can smell food from over a mile away;D), but the low fan hum is definitely noticeable when the side is on and the case is under the desk. Could the fan be on its way out also?

In case I do need a new power supply (do they even exist?), I would be interested in where I can get one from or if non-Apple branded power supplies exist (like Newertech or similar). Preferably UK/EU based if possible.

Once again, many thanks for all the help so far.

 

[Nanco]

I thought I’d just give a quick update on the situation.

Firstly, I removed both graphics cards from the Mac and did some tests by running just one at a time to see if there were any differences. Firstly, I noticed that there were no differences performance wise (under heavy load and idle), however one of them was running considerably hotter than the other.

The cooler card seemed to run fine however I noticed that the warmer card “snapped” a bit (due to rise/fall in temperatures perhaps?), therefore I’m assuming that this card may be the source of the problem.

I used to originally use 4 screens however I have been using 3 for about a year now, therefore I won’t have any use for the second graphics card anymore. I’ll check the thermal contacts and do some more testing when I have time, but for now I’m proud to confirm that I have a snap free Mac.

The problem (?) with the PSU still persists, however I’ll create a new thread for that as not to go to far off topic.

 

[chscag]

You can continue with this thread if you have any further problems that include the power supply. This way we will have a history of all that occured in one place.

Thanks.

 

[Nanco]

Problem Solved!

Hi there,

I know its been some time since I first created this thread (and the other one regarding the PSU/fan sounds) however, after a few months of various troubleshooting and trying things people suggested in this forum, I managed to figure out what was going on and believe I have finally resolved everything. I thought I’d make a final post regarding this just in case anyone happens to have the same issues in future to simply save them a bit of time (and possibly money). Some of this may seem self explanatory, however I have never really felt the need to properly dissect my Mac Pro before apart from periodic cleaning therefore a lot of it was new to me. The system had been working fine up to now so I never really felt the need to do anything else really.


1) The snap sound

As I suspected, the random “snap” turned out to be coming from the Radeon HD 5770 graphics card/s. Bearing in mind that they had been a part of this system for roughly 7 years from brand new, a part of this could have been down to general age or wear and tear.

The graphics cards appeared to work fine. I had no sporadic glitches or crashes either from within OS X or BootCamp. One thing I did notice however was how hot each card was running at (from idle, this could range from about 60-80 degrees C). I found that GPU monitoring was lacking within OS X so I began testing using MSI Afterburner from within Windows.

Using graphically intensive software increased the temperatures to upwards of 100 degrees at one point. GPU usage was peaking at 100% however it looked as if the fans would not speed up on their own past a certain point (suspected faulty sensor?) leaving me to tweak the fan speeds from within Afterburner. I managed to get the temperatures under control, however this resulted in running the GPU fans at about 60-70% max (it was quite loud). I reapplied new thermal paste and pads to each card (they were a bit worn out) and repeated the test however this literally made no difference to the temperatures.

As PCIE card fan control is not possible within OS X, I began looking into flashing the cards using Radeon BIOS Editor with the intention of matching the custom fan curve I created in Afterburner. Ultimately this didn’t work for me as it seemed like the Radeon drivers in BootCamp and OS X were overriding whatever custom settings I applied to the BIOS (there was a moment when the fans resembled the custom curve, however this was short lived when the login screen had loaded). Unfortunately I couldn’t find much information about this and what I did find went over my head so I decided not to continue with tweaking anything more at this point.

I had tested my system using a combination of the two cards simultaneously, swapping them around, and using just one at a time in different PCIEx16 slots. Ultimately this didn’t present a drastic difference in performance and temperature. One thing I did notice however was that the card temperature was determined by the number of screens plugged into the card and their resolution settings. I honestly never considered this to be a contributing factor before, but basically running two 1600x900 resolution monitors would result in temperatures of roughly 60-70 degrees on idle. That would drop to about 50-60 degrees idle if using just a single monitor however it would rise to 70-80 when plugging in a 1920x1080 monitor. Running a HD YouTube video in full screen would see an increase of about 10 degrees as an example.

I actually sourced a replacement ATI Radeon HD 5770 from a reputable Apple dealer to see if the problem was specifically with my cards. Though the card was roughly a few degrees cooler (nothing drastically different), the performance remained the same under both Windows and OS X.

In the end, I actually decided to purchase a different card (an Nvidia GTX 960) to see if this made any difference. I lost the boot screen (not really bothered), but the results were extremely favourable. I now have a card that idles within the 40-50 degrees range and reaches maybe 60 degrees when under pressure. Not only that, I can now run three monitors from this single card without exceeding these temperatures (I never had any luck with getting three monitors running off a single HD 5770 in the past despite following instructions on using active adaptors). More importantly I haven’t heard a random “snap” in weeks since swapping out the cards, which leads me to believe that the HD 5770s were at fault after all. I guess they are pretty poor cards even by todays standards.


2) The PSU & fan noises

There’s not really much I can say about this. Again, this may be obvious to some people, but for me I genuinely had no idea and wanted to try all I could to troubleshoot this problem.

Basically, the fizzing sounds that emanate from a Mac Pro PSU are completely normal but can actually be amplified depending on whether the Mac Pro is drawing more or less power for certain tasks. I sourced a replacement PSU from the same reputable Apple dealer and can confirm that the performance was no different to the PSU that had been in my system for roughly 7 years. What I did notice was that the fizzing sound would get louder when my graphics cards were put under stress (at the temperatures they were running at, its no wonder that the PSU was fizzing like crazy at times). I can only assume that the cards were drawing a lot of power.

Since replacing the two HD 5770s with a single Nvidia GTX 960, the PSU has been much quieter although it still produces a small amount of noise. This is barely noticeable though as the Mac Pro is located under a desk. I guess its safe to say that unless you are having obvious power related issues (random power outages or visual indications like smoke or sparks etc) then the PSU itself won’t need to be replaced.

The fan sound is also normal however the speed (and therefore the pitch) it was running at was making it quite annoying. I basically increased the PSU fan speed slightly using Macs Fan Control and have found a sweet spot which doesn’t sound as intrusive as it was when running at a slower speed. I guess I could one day try to replace this fan completely to see if that makes any difference, but as I understand, its not as quick of a job as it should be and I’ll probably need to book time off work to do this.

A massive thanks to everyone on the forum who contributed help. I really do appreciate it!

Kind regards,
Matt

 

[pigoo3]

I thought I’d make a final post regarding this just in case anyone happens to have the same issues in future to simply save them a bit of time (and possibly money).

Hey there Matt. Wow...you really went thru quite a bit of troubleshooting. But then sometimes that's what we go to do to get to the root cause of things.

Congrats on finding solutions that worked out for you...and of course we greatly appreciate a conclusion to a story (and even better if it's a positive conclusion)!

Maybe we need to promote you to one of our Mac Pro experts...and send all Mac Pro questions your way!

Thanks again,

- Nick

 

[pm-r]

Maybe we need to promote you to one of our Mac Pro experts...and send all Mac Pro questions your way!

I think he'll need or want one of those big hats that seem to get sent out to some deserving members.


And congrats to the OT's sleuthing and thanks for the info I'm sure some can use.



- Patrick
======