If you have new RAM in your Mac or if you are trying to diagnose weird shutdowns and problems, you should consider testing your RAM. An easy way to do so is to follow these instructions from the command-tab article “How to Test RAM Under Mac OS X“.
- Download the memtest_422.zip file and install the program.
- Shut down and then restart the computer holding down Command and S keys.
- When at the prompt, type “memtest all 2″ which will test all the memory twice.
This will take several hours to run but should diagnose the tricky problem of bad RAM.