Your view is overly simplistic. If you search this board and the official Dell forums, you will see reports about certain brands of RAM working less reliably than others. Further, some memory suppliers even state openly that their RAM is not guaranteed to work with certain Dell notebooks. Of course, most RAM comes with at least 3yr warranties nowadays, so one can order cheaply to try if it works without overheating, etc. Simply speaking, most users prefer to avoid hassles with returns by buying from more reputable vendors, and it is not true that "all RAM-s are equal".