June 9th, 2009 • 9:39 am
My three-year-old Mac Pro is equipped with an NVIDIA GeForce 7300 GT graphics card and has two monitors connected to it, a 30″ and a 23″, both Apple models.
Recently, I have started experiencing problems that seem to be related to the graphics card. I am not sure exactly when they started, but I strongly suspect it was with the Mac OS X 10.5.6 update. The symptoms are the following: Usually, I am in the process of opening a PDF file with Preview when, all of a sudden, either the display becomes completely corrupted, with pixelation everywhere and bits and pieces of windows everywhere, or the entire UI freezes and the mouse pointer, while still moving, turns into the spinning pizza of death.
When the symptoms are “only” display corruption, I seem to be able to solve the problem by quitting and relaunching the Preview application itself.
When the symptoms are a total UI freeze, I cannot do anything to regain control of the system. The force-quitting shortcut does not work, and nothing responds to mouse clicks. I have to do a hard reset of the machine.
It’s a problem that has been happening on and off for the past couple of months now. Sometimes I get a few days without any problems. Sometimes it happens a couple of times in fairly quick succession.
Whenever the problem occurs, if I look in the system log in Console, I find a flurry of error messages at the time of the display corruption/hang that seem to have to do with the NVIDIA graphics. They all look like this
Jun 8 15:44:57 Mac-Pro kernel: NVDA(OpenGL): Channel exception! status = 0xffff info32 = 0x6 = Fifo: Parse Error
Jun 8 15:44:57 Mac-Pro kernel: NVDA(OpenGL): Channel exception! status = 0xffff info32 = 0x3 = Fifo: Unknown Method Error
To me, this looks very much like there is a problem with the OS software that controls the graphics card, i.e. the video card driver for the NVIDIA card.
Of course, at this point it is impossible to entirely rule out a hardware failure of the graphics card itself, but I have done a bit of research online and found that I am far from being the only one with the problem:
MacFixIt Forums: “Display corruption and hangs using OS X 10.5.6”
Apple Discussions: “NVDA(OpenGL): Channel exception!”
I have another spare GeForce 7300 GT so I might try to swap the cards to see if it makes any difference. But really, based on the apparent prevalence of the problem and the variety of systems affected, it does appear to be not a widespread hardware failure, but an OS-related issue introduced with the Mac OS X 10.5.6 update (unless these GeForce cards are all starting to fail after a few years of daily use).
Sadly, as always in such situations, it seems to be hard to get the message across to Apple that there might be a problem with their drivers. Some people appear to have more success than me in reproducing it reliably, by using software applications that make greater user of the graphics card and presumably of the OpenGL software. I have submitted a bug report, but of course haven’t heard anything back from Apple about this.
It is really quite frustrating because, with the transition to OS X, we really thought we had left system-wide crashes and hangs behind us. But every once in a while, they seem to be able to rear their ugly heads again, in a way that really affects the perception of trust in the machine. In my case, the situation is not too atrocious yet, since the problem does not occur every day. But I still expect to be able to run my machine for many days in a row without having to reboot or risking to lose any of my work, and at this point I seem to have lost that level of reliability.