MemTest for Mac OS X Tests your RAM

If you have recently upgraded your Mac RAM or are experiencing strange system crashes, it’s a good idea to test your memory modules integrity using a free tool called memtest.

Download MemTest for Mac for Free

Memtest is from the broader UNIX world and it that has been ported to Mac OS X. For whatever reason, there are some websites who are charging for the free utility, but you should not need to pay for it:

• Download MemTest now (direct download link)

The above link downloads a zipped package installer that simply places the memtest port in /usr/bin and does nothing else.

Test your Macs RAM

Once you have installed memtest for Mac, launch the Terminal and type the following command:

memtest all 2

Memtest will take a little while (15+ minutes is not unusual) and you’ll see an actively updated screen like the screenshot above showing progress of the app. The command will test your RAM twice, which is generally enough to detect errors, but for unusual system freezes and crashes it can be a good idea to test your memory longer by removing the ’2′:

memtest all

Without specifying a number of passes at the end, the app run a long time but can be stopped any time by hitting Control+C in the terminal window. Letting memtest run a while will consume a lot of CPU cycles so if you’re going to run the utility on a Mac laptop be sure to plug it in first.

Error Reports and Bad RAM

If any errors are reported, memtest will let you know. Likewise, if you run memtest and the utility freezes or crashes, that’s a pretty good indicator that your RAM is bad. If you’re running the test and you encounter any errors or freezes, you should return the memory modules to the place of purchase and get a replacement.