Erik’s Brain

The reward of a thing well done...

Visual Effects Weirdness in Mac OS X

I almost made a post today about some issues I was having with my iMac. I had just noticed that the visual effects/graphics on my last generatio top-of-the-line iMac was performing under my expectations. Now, this isn’t a new machine. I’ve had it since October. But recently I noticed that certain things weren’t looking as smooth as I expected or as smooth as they used to look. Two examples:

  • Two specific Quicksilver panel animations were running a bit roughly. When you actually tell QS to do something, such as open an app, open a file, open a web page, email someone, etc., the panel zooms towards you as it fades out. It’s a quick transition, but I noticed that it was clearly “dropping frames” and didn’t look as smooth as I remembered it. Odd. The second QS quirk was when you cancel out of the QS panel by hitting the ESC key. When you do that, the panel squashes down vertically and stretches out horizontally as it fades out. That, too, was being rendered roughly. And as soon as the panel had drawn out, I saw, for a split second, a phantom remnant of the panel, in the size and position that it was right before you cancelled out of it. I wasn’t able to capture it with Snapz Pro or Screenflow, but it was there. Trust me!

  • In Tweetie for Mac, when you are looking at a particular user’s list of tweets, you can click on their photo in the upper left of the window to see a larger version of their picture. It shows this with a really nice animation and as you close the image, it also animates away nicely, too. This animation was playing back a little jagged, just like the Quicksilver animations. Huh… And, oddly, as you closed the user’s picture, the phantom image thing happened just like it does in Quicksilver. That is, as soon as the genie effect that draws out the image completes, you see, just for a split second, the full sized image where it was just before you told it to go away. Okay, very weird, and this is clearly not a software issue. Something else is going on.

I switched over to my older white MacBook to test things out there. This MacBook is a 2ghz machine (vs. the 3ghz iMac) and has much, MUCH weaker graphics (GMA X3100 integrated graphics in the MacBook vs. NVIDIA 8800 GS in the iMac). But everything looked great on the older, slower MacBook. WTF?!

I figured there was a problem with the 10.5.7 update I had just applied to the iMac, since the MacBook was still at 10.5.6. But, after updating the MacBook to 10.5.7, the problems remained. Once again, WTF?!

I downloaded and ran Xbench on both machines to make sure the graphics in the iMac were running properly. Sure enough, across the board the iMac wiped the floor with the MacBook, usually scoring close to twice as high as the MacBook, as I would expect. For the record, the OpenGL result for the iMac was way, way, WAY ahead of the MacBook. Graphics seemed to be fine.

That’s when I tried out the Quicksilver visual effects again. And, everything was fine. It ran smoothly. No issues at all. What?! I tried the effects in Tweetie. Same deal. All good now. Um… I don’t get it. Was the graphics card in the iMac just taking a nap? Did it need that Xbench workout to kick it in the ass to get it moving? Seriously, I have no idea what just happened. But my iMac is running great again. I’m about to reboot the iMac to see if it’s sluggish again after shutting down. Hopefully that’s not the case…


After reboot, I’m happy(?) to report that everything is back to normal. The issue seems to be resolved. The mystery is very much not resolved, though. But, if you are having problems like this, you might want to grab a copy of Xbench and run it. It might be the kick in the pants your system needs.