Thinkpads Forum

They have the same FRU number. Is there any difference between them apart from the appearance? What's the black case in the 2nd pic used for?

If it's the same FRU number it is compatible with the machine that it was intended for, that's it. It could be (and most likely is) different RAM. The black thing is a heat spreader. It is designed to disipate heat away from the RAM chips.