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Sound stuttering after Mountain Lion install

Dear community,


after having installed OSX Mountain Lion my sound startet stuttering whenever there is rapid movement on my screen.

This includes e.g. window movement, scrolling through image loaded websites or video playback (flash player, quicktime).

A restart didn't help. I'm using stereo output, not digital.


I have connected a second monitor but the problem persists after disconnecting it. Movement on the second monitor also causes the sound to stutter.

My GPU Diode temperature is at 85°C (there is some bug that keeps the GPU under load while a second monitor is connected AFAIK), but I guess it was the same under Snow Leopard.


In Snow Leopard the sound output was always perfect even under heavy load or heavy HDD I/O.


Any ideas?

iMac (27-inch Mid 2011), OS X Mountain Lion

Posted on Jul 28, 2012 5:48 AM

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Question marked as Top-ranking reply

Posted on Jul 28, 2012 3:22 PM

I am also having this issue as well.


I opened Activity Monitor and noticed that during the stuttering, coreaudiod jumps in CPU usage, often past 5%. I have also noticed graphics lag when this occurs if I'm doing something like watching full-screen video or gaming.


I'm currently experiencing this on mid 2011 iMac 27" as well as a 24" iMac 2009 model I use at work.

1,223 replies

Nov 24, 2012 7:45 AM in response to pepper_chico

Others are trying to get different models involved in this thread which originally targeted the 27" iMacs. A failing hard drive wouldn't cause the audio stutter. At least the symptoms wouldn't be the same. In all my years on a PC I've never seen a failing drive cause that. I have seen bad drivers and firmware do this before in a different manner.


The graphic switching doesn't pertain to the iMacs, but again, is a software glitch. When it is happening on new machines with SSD drives, it seems pretty straight forward. Mountain Goat does run the machine even hotter due to fan throttling and apple allowing the hardware to run hotter in the name of quiet computing. But that in the long haul will have many negative ramifications.


Without over analyzing this, many of these things all happened at the upgrade. Many have said it lessened or was eliminated by reverting back to Lion. If it was bad blocks, then it would not do it on a reinstall or if you partitioned to a different part of the drive. That is because the OS writes files in a different spot. If this was heat related, a cold computer with processor temperatures in the 40C range would not do it, but it does.


The point is this IS software. I'm holding Apple's feet to the fire on this one and have made a fair bit of noise with them thus far. But I'm about to make a lot more noise shortly. I've gotten tired of calling apple and being told their engineering department doesn't know about this issue. They obviously do as they reached out to several of us, myself included. So I'm keeping all my documentation on this and backing everything up as I move forward. I've given them the option of a capture on my systems, requested a refund, and they wish to quote by saying they do not engage in this behavior. Being amicable seems to get you only an apology. But like Apple has done with Samsung, this appears to be increasingly the only language the DO understand. I have two coals left on the fire at this point. Once they are extinguished, I'm sad to say I'll have to resort to plan B.

Nov 24, 2012 7:59 AM in response to BarrettF77

this is the exact thing. its a software fault, not a hardware fault.

sorry but i can't be that i bought a 2200 Euro system and it stuttering in using youtube which can easily used by a 400 windows notebook ...

i didn't called apple because you did it and there wasn't any result ... maybe if i have time in the next weeks i will call them ... but i think there will be no result ...

so I hope they will look up this thread ... it's mainly a fault on the imac 2011 i guess.

Nov 24, 2012 8:03 AM in response to eSudio

I would highly encourage anyone and everyone that is affected with this issue to contact Apple and continually keep bugging them and ask what is being done about it. To keep bugging them over the issue is seemingly one of the only ways to make them aware. It's obvious they wish to turn a blind eye on this matter, but if the issue is not Going to be fixed, they owe it to customers to make this right in some other fashion.

Nov 24, 2012 8:22 AM in response to BarrettF77

You are wrong.


As I mentioned before, people should not mistake what the issue is about, the issue here is "Sound stuttering after Mountain Lion".


Solutions were presented before for specific systems, and should not be ignored.


This thread is not about iMacs, the OP had an iMac, if it were about iMacs, it should have been explicit in the thread title or section.


I'm here since page 5, before you, and before that page people were already talking about macbooks, retina macbooks, presenting the same problems.


Take notice about the issue please, and anyone that found a cause/solution, don't hesitate explaining and helping.

Nov 24, 2012 8:29 AM in response to eSudio

It's ridiculous how long this issue has affected people and no communication from Apple !!! We don't even know if they are working on this issue !!! I've bought the best iMac (which was my most expensive computer I ever buy) to have something that last et that was powerful. With Montain Lion ("the most advanced operating system in the world" ????) I have now the worst computer I ever own. Even my previous crappy PC did a better job ! I can't even make a movie, listen music or watch youtube without sounds issues and mouse lags.


Even CNET made an article on this issue the 9th AUGUST !!! And we still have no correction and no communication from Apple.


http://reviews.cnet.com/8301-13727_7-57489874-263/sound-stuttering-after-mountai n-lion-installation/


This iMac will be my last Apple product. Even the crappy 300$ netbook I bought 3 years ago is more usefull now than my 3000$ iMac.

Nov 24, 2012 8:45 AM in response to eSudio

I agree - it's not just about iMacs. I found this thread by searching for audio dropouts in ML, which were a pretty serious problem for me. So it's about audio. Since I have a new, mid-2012 Macbook Pro, I couldn't run any earlier system than ML, so I couldn't really isolate the problems to the OS version. However, from my experience it seemed that the problem started after the firmware update that accompanied 10.8.2.

As it turns out, a firmware update for my SSD (Crucial M4) seems to have solved the problem. This is a little strange and unexpected, since the new firmware appears to be "fixing" a problem that a previous firmware update from Crucial already fixed on the late-2011 Macbook Pros. Anyway, who knows... But I do still have a feeling that the initial cause of my audio problems was the firmware update that accompanied 10.8.2. More to the point, however, is the fact that it probably isn't any single issue, but rather a mix of issues that's slightly different for each machine. Hence the delay in getting a fix...

Nov 24, 2012 9:14 AM in response to tttxx

I can switch between SL and ML on my 27" iMac.


SL runs flawlessly, ML is all bugged out on the same machine.


It's not only this bug, the more I've used it the more other bugs have come up including the known WiFi bug, iTunes frezzing up, and now quicktime actually stopped working!!! Quicktime??!


I've been mac for decades, never had problems, this Mountain Lion business is junk.

Nov 24, 2012 9:22 AM in response to MoogNinja

I have to agree about ML. But I also have to add that I think it really started with Lion, and ML just compounded the problems. I have to admit to liking some of the new features, but ML really is a bloody mess. The first thing that needs rethinking is Auto Save. Nice idea, but a bit of a disaster in implementation. As far as all the iOS-style toys are concerned, I don't care either way. They just need to be optimized to ensure they don't mess with the core system (read: audio).

I'm really, really, really hoping that 10.9 is the kind of Snow Leopard of the Lion generation - that is, just as Snow Leopard fixed and optimized everything added in Leopard, <something> Lion will fix and optimize all the stuff added in Lion and ML. Probably wishful thinking, but that's what I'm hoping for.

Nov 24, 2012 10:16 AM in response to wheetabix

I have too say that my user experience was almost exactly like yours, till the point it became unbootable and I checked my HDD with a working tool, not Apple useless disk utility.


Snow Leopard: Never had a problem.

Lion: Some slowness and spinning wheels.

Mountain Lion: Serious slowness and Media stuttering (never experienced before)


Didn't get the same behavior with other OS in the same disk.

Reinstall didn't solve.


Got it to become unbootable, really, even other OS refused to boot.


Start analisys through a linux live session, HDD readable, but full of bad blocks (Apple disk utility never warned about that, it only suggested repair, which completed successfully. It's kind of useless).


It got me a long time to go and CHECK THE HDD WITH THE RIGHT TOOL. *My case* was the HDD, still, it was usable, it was just ML that dealt really poorly with bad blocks compared to the other/previous OS, so it helped me think it was only ML to blame. Conventional apple diagnostic tool also helped for that.


As I underline, it was just my case.

Sound stuttering after Mountain Lion install

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