X120e - Aftermarket memory causing BSOD, unstable boot

Question

Purchased a 4gb stick of GSkill memory (F3-10600CL9S-4GBSQ, CL9-9-9-24) hoping to get a little extra memory in my system. However, it seems to make my computer extremely unstable - restarting several times before getting to the login screen, flashing BSODS about sytem hangs and a memory error - both with and without the 2gb stick, and in both slots, often after waking from hibernation. I ran Memtest86+ and the windows memory test, and both seemed to pass alright. Since the 2gb stick by itself seems to work, I was planning on returning the new stick, but was wondering if you all knew of a more likely-to-work thing of memory for the computer.
Thanks for your help!

Answer 1

Buy the memory that has a Lenovo FRU number on it. You can buy direct from Lenovo or search for the memory FRU numbers and buy them from online retailers.
An additional advantage to buying a Lenovo FRU is that it's covered under the notebook's warranty, so if the memory goes bad during the warranty period, you can get a replacement from Lenovo without having to ship the bad part back first.