Hardware teszt
http://www.info.apple.com/support/aht.html
https://github.com/upekkha/AppleHardwareTest
http://www.macissues.com/2014/03/21/how-to-run-and-interpret-apples-hardware-tests-on-your-mac/
https://www.raymond.cc/blog/memory-test-for-macos-x/