Yep, its memory. DDR3 4Gb PC3 10600. Fitted into my sons netbook as it should, with no problems what's so ever. My son reports that the response times have improved in all areas. Note he was running with a 1Gb DDR3 card before the upgrade. It should also be noted (and yes we were aware) that Windows 7 Starter will only use 2Gb of the memory, but it sees the whole 4Gb. Buy a 2Gb card if you don't intend to upgrade your operating system form Windows 7 Starter. Was it worth doing the upagrde? Yes it was.