10.4: A temporary fix for an Exposé slowdown

May 31, '05 10:10:00AM

Contributed by: MBHockey

Tiger only hintSeemingly everywhere I turn on Mac forums, users are reporting that Exposé on 10.4 seems unnecessarily choppy with more than three windows (whereas Panther handled this task fine). This problem has been plaguing me for some time now, and it wasn't until yesterday that I began trying to figure out a solution. After an unsuccessful fix of zeroing of my hard disk and doing a full 10.4 system reinstall, I began poking around the graphics tools that come with XCode 2.0 -- since it obviously wasn't related to some third-party program.

I found a property called Beam Sync in a Developter Tools program called Quartz Debug that, when disabled, made Exposé work just as it did on Panther for some reason unknown to me. I'm not exactly sure just what Beam Sync is, which is why I am not entirely sure of the consequences of disabling this -- use it at your own risk! So if you have been having problems with Exposé being choppy on 10.4 even with your Dual G5 and 9800 graphics card, try the following steps:

  1. Install XCode 2.0 from your Tiger install DVD (if it isn't already installed)
  2. Go to /Developer/Applications/Performance Tools
  3. Run Quartz Debug
  4. From the Tools menu, select Show Beam Sync Tools
  5. Click Disable Beam Sync
  6. Force Quit the Quartz Debug application (you need to force quit to make the changes "stick;" regular quitting will re-enable Beam Sync upon quitting)
The catch to this is you will have to do this each time you reboot your computer. But I usually leave my PowerBook on for weeks before I need to reboot, and it's a decent workaround for the time being. Hopefully this will get completely ironed out come 10.4.2.

[robg adds: I haven't noticed any slowdowns in Exposé on either my desktop or PowerBook, but I have seen similar complaints in a few forum threads on various sites.]

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