Starting in 10.8.x and continuing in 10.9.2, I notice my system freezing when running a time machine backup while "higher performance graphics" are enabled.
When I say "freeze", I mean that the mouse pointer doesn't move anymore, sound stops, no more updates to the screen, no ping anymore, cannot log in via ssh anymore. Only pressing the power button for several seconds turns off the system.
I am still running a 17-inch, Mid 2009 model with two graphics chips, a nVidia 9400M and a 9600M GT. Contrary to newer models, switching between the chips is a manual process that requires logging out and back in. For playing games, I switch to the 9600M GT chip.
I started noticing the system freezing while playing games and running a time machine backup in the background some time last year. At first, I suspected the game I was playing had a bug. With time machine enabled, the system would start freezing shortly after the backup had started. With time machine turned off, no further freezing could be noticed.
One suspicion was that the system may overheat. Just in case, I got a cooling stand. However, today, I had forgotten to switch back to the 9400M and manually triggered a backup. It went fine for hours and suddenly froze when I started using Safari. The system was definitely nowhere near a high temperature or even under significant load at that moment.
There are no freezes with time machine whatsoever when using the 9400M graphics.
The time machine backups are run via WiFi to an external hard drive connected to an AirPort extreme.
So to summarize:
- time machine freezes system reproducibly with 9600M GT
- temperature does not appear to be an issue
- problem started with 10.8.x and continues on a freshly installed 10.9.x (although the 10.8.x data was migrated onto the 10.9.x)
- problem does not seem to be related to a particular application
Did anyone make similar experiences?