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What are the best possible RAM tests that can be run on a MacBook Pro (Early 2011 running Mountain Lion) after upgrading RAM from 4 GB to 16 GB?

I see there a quite a few tools out there and the Apple CD hardware test itself.

I figured I'd ask here hoping to get a much more educated, experienced and consolidated answer.

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As someone who has to test RAM every day (Apple Certified Macintosh Technician for 2.5 years), I've found that the best RAM testing utility hands down is Memtest.

It's really easy to use too! First, copy it to /usr/bin then boot to single-user mode. Next, type in mount -uw / to mount your internal drive (for logging purposes) and finally type in memtest all -L 3 to start the Memtest suite.

If you want to perform more loops, change the 3 to a number you desire (e.g. memtest all -L 5), I reckon 3 to 5 loops is the best because it gives the RAM time to heat up (intermittent RAM failures can be heat related).

edit: Just wanted to add that Apple Hardware Test is useless, so never use it for testing hardware, especially RAM.

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The link goes to a site that's down. Via I found this direct link: . "Apple Hardware Test is useless": What specifically is useless about it? – Matthew Cornell Mar 11 '13 at 18:12

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