Mountain Lion randomly causing screens to go black - keyboard unresponsive

Question

Mountain Lion randomly causing screens to go black - keyboard unresponsive

Since upgrading to Mountain Lion a few days ago, my Mac Pro 3,1 (early 2008) has begun randomly "going black" - both of my monitors go black (just like during a display sleep), but I can't wake them. The machine apparently continues to run (Time Machine backups continue to accumulate, sound continues playing, etc...), but the keyboard is seemingly unresponsive (I cannot, for example, force a restart with control-command-eject); I am forced to shut down the system each time by pressing and holding the power button.

There does not seem to be a pattern to the blackouts, but they seem to happen more often when the machine has been idle for a short while. GPU activity seems to encourage the blackouts (which makes me suspicious of the video card or graphics drivers), but the problem still sometimes occurs when just sitting idle with the desktop displayed and not much of anything going on. I have never had a problem like this before, and previous to installing ML, I was running Lion just fine. After these blackouts, I go to check for crash logs, kernel/GPU panics, etc, but can't find anything more than just standard system log stuff.

My machine is a Mac Pro 3,1 (early 2008). More detailed specs follow at the end of this message. A few years ago, the original video card died on me, so I replaced it with an ATI Radeon HD 3870. Other than that, my SuperDrive doesn't write anymore, so I've installed a second optical drive (Lite-On iHAP222, ATAPI). All four hard drive bays are full, but the machine is otherwise basically stock.

I have installed a completely clean, fresh copy of ML from a DVD onto a newly formatted HD, and I have installed absolutely *nothing* else, and the blackouts still happen (so I've ruled out any third party software). I've also zapped PRAM and reset the SMC. I've turned off all Energy Saver options (machine, display and hard drive sleeping), and I've tried disabling the screen saver. None of that helps. The only thing that seemed to fix the problem is running the machine in "Safe Mode". My understanding is that Safe Mode will disable graphics acceleration, which becomes clear by the rough graphics updates. So my best guess is that ML does not play well with my ATI Radeon HD 3870, at least not on an early 2008 Mac Pro. But that still doesn't explain why the keyboard goes unresponsive.

In any case, before I shell out a few hundred bucks to try out a new video card, is anyone else having this problem? Any thoughts or additional things to try first?

Much Thanks,

Tom

Detailed Specs:

Model Name: Mac Pro

Model Identifier: MacPro3,1

Processor Name: Quad-Core Intel Xeon

Processor Speed: 2.8 GHz

Number of Processors: 2

Total Number of Cores: 8

L2 Cache (per Processor): 12 MB

Memory: 8 GB

Bus Speed: 1.6 GHz

Boot ROM Version: MP31.006C.B05

SMC Version (system): 1.25f4

ATI Radeon HD 3870:

Chipset Model: ATI Radeon HD 3870

Type: GPU

Bus: PCIe

Slot: Slot-1

PCIe Lane Width: x16

VRAM (Total): 512 MB

Vendor: ATI (0x1002)

Device ID: 0x9501

Revision ID: 0x0000

ROM Revision: 113-B3390F-270

EFI Driver Version: 01.00.270

Displays:

PA271W:

Resolution: 2560 x 1440 @ 60 Hz

Pixel Depth: 32-Bit Color (ARGB8888)

Main Display: Yes

Mirror: Off

Online: Yes

Rotation: Supported

DELL S2409W:

Resolution: 1920 x 1080 @ 60 Hz

Pixel Depth: 32-Bit Color (ARGB8888)

Mirror: Off

Online: Yes

Rotation: Supported

Mac Pro, OS X Mountain Lion

Posted on Jul 30, 2012 12:43 PM

Reply

Answer 1

Best reply

Laura Frank

Level 1

10 points

Aug 1, 2012 6:47 AM in response to Tom Pinkerton

I have the same issue with a Mac Pro 5,1 mid 2010. It started with Lion and continued with Mountain Lion. I still have Snow Leopard installed on another internal drive and now the problem exists there too.

Thinking I had a heat issue, I installed smcFanControll with Mountain Lion and have hours of use if I run the fans at their top speeds, but the computer will only run about 10 minutes without the fans software running.

I've called Apple and my case is in progress. I will post back if I get any useful information.

Mac Pro 5,1

2 x 2.93 GHz 6-core

24 GB 1333 MHz DDR3

ATI Radeon HD 5870 1024MB

Reply

Answer 2

Aug 1, 2012 9:31 AM in response to Laura Frank

The heat issue prompted me to have a closer look at my video card, and the fan/primary heat sink was pretty clogged with dust and such. I've blown out and vaccuumed the card (and other internals) and will see if that solves the problem. If the card has been close to overheating, perhaps ML pushed it over the edge, or maybe it was just coincidence. In any case, I'll report back if this solves the problem. I also have a new card on the way (ATI Radeon HD 5770) if the problem persists. It was a good time to upgrade my graphics anyway, I suppose.

Thanks for your response.

Reply

Answer 3

Aug 1, 2012 2:39 PM in response to Tom Pinkerton

My computer looked squeakly clean on the inside, but I took a can of compressed air to in anyway, and the temp gauge on the PCIe slot is reporting it's running 50 - 60 degrees F cooler!

Apple Support is suggesting the next step is for me to take the computer in for hardware repair if the problem continues, but I think my problems is solved.

Reply

Answer 4

Aug 1, 2012 3:10 PM in response to Laura Frank

That's a big temperature drop!

I'm cautiously optimistic myself, as I haven't had a "blackout" since cleaning up the video card. I guess it doesn't take much to clog up the heat sink/fan vent. Keeping my fingers crossed...

Reply

Answer 5

M.A.C.

Level 1

4 points

Aug 19, 2012 9:29 PM in response to Tom Pinkerton

Tom, after installiong OS X V 10.8, my Mac Pro Early 2009, 2 x 2.93 Quad, 32 GB ram, 4, 2 TB hd NVIDIA GeForce GT 120 512 MB with dual displays. The displays would go off and Could not be woke up b y the usual touch of the keyboard or the trac pad, I had to shut down at the power button and re-boot. I'm thinking it's a bug to be fixed in an update. In the mean time I discovered that when the displays go off they arn't asleep and if I use the keyboard shortcut for sleep, option-command-eject keys, the displays sleep and can then be woke the usual way. So far this has worked for me. Give it a try

Reply

Answer 6

Aug 20, 2012 7:41 AM in response to M.A.C.

In my case, I've concluded the problem was a clogged fan/heat sink vent on my video card which caused the card to overheat. Ever since cleaning that out, I haven't had a single problem (it went from blacking out multiple times a day to zero since). The fact that the blackouts coincided with installing 10.8 leads me to believe that maybe the 10.8 screen saver works the video card a little harder, and that pushed mine over the top. In any case, if you haven't already, I would take a close look at the heat sink vent on your video card. Even if it looks clean on the outside, lint and dust can still get trapped inside the vent. I used a combination of air blower (one of those bulbs used to blow dust off of camera lenses) and a vaccuum to clean mine out.

Thanks for the response.

Tom

Reply