Rember is a free and easy to use graphical front-end to the command line MemTest tool, it runs memory tests to help determine if you have defective RAM modules installed in a Mac, which could potentially lead to crashes and general system degradation.
Using Rember to Test Mac RAM
As with memtest, it’s best to quit as many open applications as possible so that you have the maximum amount of free memory available, this allows more RAM to be tested for any potential problems.
Launch the app and click on “Test” and then just wait. Assuming all goes well, you’ll get an “all tests passed” message, but if something went wrong, you’ll find that out too.
What if the test doesn’t pass? If you’re using third party memory, you can usually just replace the RAM module and resolve the issue. Most RAM is covered under the manufacturers warranty, and if it is Apple RAM and your Mac is still under Apple Care warranty than Apple will replace it for you.