I've got a Lenovo x121e. It servers as my windows development and VM machine. Until recently its only had 8gb ram, and the time came to see if I could get 16gb in it. I couldnt find much on the net about these laptops being able to support this much ram, so I took the plunge and purchased some 8gb Kingston pc 10600 SODIMM modules. They're cheap ($65 AUD), and as it turns out, they work fine. The core i3 cpu is meant to be able to address up to 16GB of ram, and the x121 fully supports it too. Awesome.