You will have to actually look inside the computer to find out how many sticks you have and what brand they are. Most Dells that I have worked on had either Nanya or Infineon memory. It is best to find out the specs on what you currently have before buying new if you plan on using your current memory in conjunction with new. For example, your machine may be capable of using PC3200, but you may only have PC2700. So, if you bought PC3200 it would work, but only run at a PC2700 speed. So in this example, there really would not be any point in buying PC3200, unless it was actually cheaper. Why don't you look inside and tell us what your current RAM is, and also post your Dell model number.