Performance problems or other issues? Make sure apps aren't running under Rosetta

Published Tuesday, July 31st

We've previously noted that performance issues can be caused by inadvertently running universal binaries under Rosetta. Most recently, we reported this phenomenon in conjunction with Firefox 2.0.0.x.

Users have since reported similar occurences, this time with regard to playback of QuickTime media in Web browsers. One reader writes:

"(I was) having stuttering and audio glitches with QuickTime 7.2 Turned out Safari had been set to open in Rosetta, which also loaded QT components with Rosetta. Having Safari Open at the same time caused QT Player performance to suffer. Turning off Rosetta in Safari and/or quitting solved the problem."

To make sure an application is not running under Rosetta, follow these steps:

1. Quit the application if it is running
2. Using the Finder, locate the the application and select it.
3. Go to the "File" menu and choose "Get Info."
4. Make sure that the "Open using Rosetta" box is not checked (see screenshot to the right) for an example

That said, there are some valid reasons for running some applications, specifically Web browsers and other apps that use plug-ins, under Rosetta.

Problems with plug-ins occur when an application is run natively in the Intel environment, but some plug-ins have not yet been updated and attempt to run in PowerPC (Rosetta) mode. When this happens, Mac OS X is unable to separate the tasks and simultaneously run the application in native Intel-mode but the plug-in in PowerPC (Rosetta) mode. Hence you should force such applications to run in Rosetta under these circumstances (if you need to make use of the plug-ins).

Feedback? Late-breakers@macfixit.com.

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