I have a Dell Dimension 8200 and I´m trying to upgrade it by installing a higher RAM memory card and a high qualified video card. About the video card, I have Nvidia GeForce. What´s better than that? Radeon? I need something powerfull to play games such as Silent Hill 4, which can´t run with my Nvidia card. Also, about the RAM memory, do I have to worry about the compatibility with my Dell or any specific brand or are these cards in general for Desktops?