Chosen Solution
I have a late 2011 MacbookPro. I upgraded the RAM from 4GB to 16GB Corsair today, but the computer would not restart. It would get to the Apple logo, then freeze. Whenever I run the diagnostic test on either one or both of the new RAM cards, they pass. However, I can’t seem to load the operating system (even in safe mode) with the 16GB installed. I just re-installed one original 2GB card and one 8GB card together and the computer started without a problem, even though the cards are from different manufacturers and of different capacities. Yet, using two 8GB, it freezes. Thoughts?
Your MBP should be able to accept two 8gb sticks of ram but it sounds like either one or both of your new sticks is bad or, more likely, that the ram you purchased is not compatible with your laptop’s motherboard. Just because it’s the correct version of DDR does not automatically mean it will work in your computer. There are other factors like speed and latency, buffered vs nonbuffered, etc. My advice is to order your ram directly from the manufacturer and have them confirm beforehand that it’s the right spec for your computer. In the meantime, just to be sure that the new ram is the problem, swap the original ram back in and see if the computer boots
