The new ones have fewer number of chips per module... even though the manufacturer product number is the same, the way the modules are made must be different because the new ones do not work and look different (unless I got two bad sets in row which seems unlikely)

I had purchased a cheaper set of RAM that arrived DOA

I had purchased two different set of memories from Crucial before these, but none of them worked in my computer and I had to return them

so I thought maybe I just got a bad set of modules

First set failed after a few months on MacBook Pro. Amazon was great sent a second set no charge installed on Mac still working.

Not really a fan after two defective sets of RAM.Be warned.-TM

I t was super easy to put it