I am looking to upgrade my nVidia GeForce MX 420 graphics card. I have a Dell Dimension 4550 desktop with an AGP port. What are some good AGP nVidia graphics cards that I should look at? Another question, when I install a new graphics card in my computer should i also upgrade other things like memory or anything? Would i have to upgrade anything else for this graphics card to make it work properly? I have stock everything in my computer.