Fix for kernel panics on Mac Pro with multiple GeForce cards: ATI Radeon HD 5770

Posted by Pierre Igot in: Macintosh
August 1st, 2013 • 9:08 am

In the summer of 2012, Apple started seeding early builds of the OS X 10.8.2 update. As a member of the AppleSeed program, I was able to test these early builds. I quickly noticed (as one would) that they introduced a serious new bug that caused frequent kernel panics on my Mac Pro, up to several times a day. I of course immediately filed a bug report on these kernel panics.

In September 2012, the final version of the OS X 10.8.2 update came out, and the kernel panics were still there. Around the same time, Apple sent me a response to my bug report indicating that the problem was a “known issue” and closing my bug report as a “duplicate”. Meanwhile, a thread discussing the issue appeared on the Apple forums, and it quickly became apparent that the problem could be narrowed down to people running Mac Pro computers with multiple GeForce video cards driving multiple monitors, and involved a few kernel extension files that were updated in OS X 10.8.2.

In October 2012, Apple released an update called OS X 10.8.2 Supplemental Update, which updated one of the kernel extensions involved. Sadly, it quickly became apparent that the supplemental update did not fix the kernel panics.

In late 2012, Apple started seeding early builds of the OS X 10.8.3 update. It included updated versions of all three kernel extensions involved in the kernel panics. The update did appear to have an impact on the frequency of the kernel panics, at least on my machine. But it failed to eliminate them completely.

In March 2013, the final version of OS X 10.8.3 came out. Again, while it included updated versions of all three kernel extensions involved in the kernel panics, it failed to completely eliminate the kernel panics.

Meanwhile, Mac Pro users managed to identify various ways of dealing with the kernel panics. I myself provided a hack that offered temporary relief, at least for some people. But it was not a fix.

I purchased an expensive Mini DisplayPort to Dual-Link DVI Adapter, which enabled me to connect both of my Apple Cinema 30-inch displays to the same GeForce video card and stop using the second card. This eliminated the kernel panics altogether, but it also had a noticeable impact on video performance and general system responsiveness, undoubtedly due to the fact that my system now only had half as much VRAM and video card processing power available.

Some people in the Apple Discussions thread also mentioned that replacing one of the GeForce video cards with an ATI Radeon HD 5770 appeared to provide a permanent fix for the problem.

Personally, I went back to using my two GeForce cards when Apple started seeding OS X 10.8.3, which enabled me to continue to monitor the situation, but of course also meant that I continued to experience the kernel panics, albeit less frequently. This remained true with the final OS X 10.8.3 update, and with early builds of the OS X 10.8.4 update.

In June 2013, Apple released the final version of OS X 10.8.4, and it still did not fix the kernel panics. As I indicated at the time, it looked like Apple was working on the problem, especially since “graphics drivers” was listed as a focus area during the testing of early builds of the update. But the fact remained that the kernel panics were still there in the final version of OS X 10.8.4.

In spite of my willingness to voluntarily endure some level of computing hardship in the name of helping Apple improve its products, I finally decided that I had had enough, and purchased the ATI Radeon HD 5770 upgrade kit myself.

I installed it in early July, and I can now confirm, one month later, that it is indeed a permanent workaround for the problem. (I am reluctant to call it a “fix” myself, because the problem might be still there on the software side of things. But the upgraded hardware prevents OS X from encountering the software problem in the first place, so it’s as good as a fix.) I have not had a single kernel panic since installing the video card.

I can also confirm that installing the Radeon card is fairly straightforward and, for those (like me) sensitive to noise issues, I can also confirm that, even though the card is bulkier and more powerful and requires its own power supply, it has no substantial impact on the overall sound level produced by the Mac Pro. (Sound is a very subjective thing, and there are multiple factors involved. In the summer, for example, when it gets really hot, there is definitely more fan noise coming from my Mac Pro. But I don’t believe the situation is any different from what it was with the two GeForce cards.) Also, while the Radeon 5770 upgrade is listed for “Mac Pro (Mid 2010)”, it works just fine in my 2009 Mac Pro.

Of course, the card has double the VRAM of the GeForce and more processing power, so there is also a little bit of a boost performance-wise. But it’s the kind of small boost you very quickly get used to, and I don’t think I would say that it provides a significant improvement over driving the two Apple Cinema displays with two GeForce cards. It certainly does not appear to be worth purchasing if you are not having kernel panics to begin with.

The bottom line here is that Apple has failed Mac Pro users. While I cannot verify that the bug is still there in 10.8.5 (Apple has been releasing early builds for a while now), I wouldn’t be surprised if it turned out that it still is. How Apple can justify “knowing” about such a serious issue and not doing anything about it for several months or, indeed, nearly a year now, I just do not know.

As I said before, the cynical in me cannot help but wonder whether Apple is not just taking advantage of the fact that Mac Pro users (especially those with multiple monitors) tend to have more disposable income and don’t mind spending several hundred dollars to work around a problem created by the company in the first place. I know that, personally, being able to do my computing in an environment free of kernel panics is definitely worth the nearly $500 that I have now spent on this problem (not to mention the countless hours spent testing, bug reporting, and simply rebooting and restoring my work environment after crashes).

But it’s definitely not right, and Mac Pro users have every reason to be pissed off with Apple right now. (I am past that stage, but that’s mostly because I have taken steps to work around the problem and I have other important issues to worry about in my life these days.) Apple has let us down big time, and while there are still reasons to be excited about the new Mac Pro announced earlier this year, it will take more than a little effort on Apple’s part to repair its relationship with those affected by this very serious and (as yet?) unaddressed issue.

One Response to “Fix for kernel panics on Mac Pro with multiple GeForce cards: ATI Radeon HD 5770”

  1. Betalogue » OS X 10.9 (Mavericks): Video corruption in Safari says:

    […] The irony here is that the main reason that I have an ATI Radeon 5770 card in my Mac Pro instead of the second GeForce GT 120 that I originally used to drive the 30” Apple Cinema Display is that there is (was?) a serious bug in OS X 10.8 (Mountain Lion) that would cause frequent and uncontrollable kernel panics on my 2009 Mac Pro with two GeForce GT 120 driving two displays. Now, that particular problem was definitely not limited to me, and many other Mac Pro users with dual monitors had the same issue. There again, it took so long for Apple to even acknowledge the issue, and the kernel panics were so disruptive, that I ended up purchasing and using the ATI Radeon 5770 card as an expensive fix for the problem. […]