If you're using only the original dell ram, then go by cpuz. If you've added some different ram, then you may have an issue. Dell boards are designed to only work with dell approved ram. But this doesn't mean your ram won't run. If you want to upgrade, then never buy a dell, hp, etc. Build your own instead. Here's a few videos from youtube: http://www.youtube.com/watch?v=iBe6w4Vvcbk.