Mac OS X 10.6 (Snow Leopard): Performance and video issues

Posted by Pierre Igot in: Macintosh
September 21st, 2009 • 4:57 pm

The consensus around Snow Leopard is that it is a system upgrade that actually improves Mac OS X’s performance on your existing hardware. Since I installed Snow Leopard a couple of weeks ago, however, I cannot say that my own experience confirms this widespread view.

Performance is not markedly worse overall, but it’s not really any better either. And there are several areas where there has been a noticeable degradation in performance, at least on my machine (a three-year-old Mac Pro with 5 GB of RAM and four internal hard drives).

For example, one of my biggest pet peeves with Spotlight in Tiger (Mac OS X 10.4) was that the “as-you-type” processing of search requests simply didn’t work and that you typically had to deal with lock-ups of several seconds while Spotlight was searching for matches for an incomplete text string that you were in the process of typing.

Leopard (Mac OS X 10.5) was a huge improvement in that department. While I still didn’t like the fact that Mac OS X started processing the search request as soon as I started typing, at least the overall responsiveness of the Spotlight menu was much better.

With Snow Leopard, however, we seem to have taken a step back. The situation is not back to the atrocious performance levels in Tiger, but it is markedly worse than it was in Leopard, and the only thing that has changed on my machine is that I have upgraded to Snow Leopard. It is not like my collection of files has doubled all of a sudden or anything like that. Snow Leopard’s Spotlight has to deal with the same amount of data that Leopard had to deal with, and it just does not seem to be doing as good a job of processing my search requests as I type in a way that does not trigger unnecessary searches or interfere with my typing.

So that’s the first major disappointment. Then there are several areas in which the system seems to be experiencing “hiccups” that simply didn’t exist under Leopard.

For example, right now, when I try to bring up the “Print…” dialog in Safari in order to print a web page or save it as a PDF, I often have to deal with a fairly long waiting period, during which the cursor changes to the Spinning Beach Ball of Death, there is tons of hard disk activity, and I am unable to switch to another application to do something else while waiting for the dialog to appear.

Eventually, the hard disk activity stops, the dialog box appears, and I do regain control of my system, but it is still rather annoying to have to wait for something that used to work almost instantly in Leopard (where I was already using Safari 4, so I don’t think that the Safari application itself is the culprit, although of course I don’t know for sure as the Snow Leopard version is not the same as the Leopard version).

What is specific to Snow Leopard about these hiccups is that, while the cursor (the Spinning Beach Ball of Death) is still moving, I cannot switch to another application, so that means it is not an application-specific fit of unresponsiveness. It is something that affects the system as a whole, at least as I interact with it. It also makes it that much harder to troubleshoot, because I cannot look at Activity Monitor to see what’s going on or try to capture a “sample” of the locked-up application. (I guess I might have to try and run to my other Mac Pro and login remotely and capture a sample through the command-line interface, although if it is a system-wide problem, capturing a sample of the Safari process itself probably won’t give any useful information.)

And these hiccups are not limited to the “Print” dialog box in Safari. I have occasionally experienced them in other unrelated contexts. I had one this afternoon while typing text in a Pages document, for example. Here again, I eventually regained control of my machine, but it was troubling and inconvenient just the same.

It is also possible that these hiccups are somehow related to the GeForce 7300-specific video card driver issues that are currently making Path Finder unusable for me under Snow Leopard. I have already talked about those and, while there have been several Path Finder updates since, I am afraid the problem is still there. As soon as I have Path Finder running, it does not take very long before the entire system locks up in a way similar to the one described above, and the lock-ups keep occurring again and again, to the point that I have to quit the application.

I also get lock-ups without Path Finder running, but they are definitely much less frequent and mostly limited to specific areas, such as the “Print” dialog in Safari.

What seems to confirm that these performance issues are part of a cluster of problems that appear to be related to video card driver issues is that I also cannot help but notice an increase occurrence of weird screen artefacts, specifically with the contents of document windows in various applications (including Pages and Preview) temporarily going black or becoming scrambled. These things usually resolve themselves within seconds, but they are still very much noticeable.

And since they resemble so much the symptoms I used to experience under Leopard, with the “channel exception” errors apparently involving my GeForce 7300 card, I cannot help but think that both the lock-ups and the weird window artefacts in Snow Leopard are part of the same fundamental problem.

That might mean that these problems only affect Mac Pro users with GeForce 7300 cards, and even possibly only a subset of them. I have no way of verifying this. But certainly these problems are not affecting everyone. Otherwise we would all know about it.

The good news in all this is that, in Snow Leopard, while the lock-ups are annoying, at least I eventually regain control of my system and I can continue to use my machine. I have not had to do a single hard reset since upgrading.

And the other good news is that, as reported a couple of weeks ago, the channel exception errors are a known issue, so there is hope that they will be solved through a system update and that this will solve both the video artefacts and the lock-ups at the same time.

But until then I am afraid I have to report that Snow Leopard has been a bit of a disappointment so far for me on my Mac Pro. There are things that I very much appreciate (such as the much-improved handling of text selection in multi-column PDF documents in Preview), but these performance issues are front and centre and make the whole experience rather underwhelming (along with the “growing pains” of the transition to the 64-bit architecture).

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