I'm updating my graphics card, and i'm trying to avoid buying a new motherboard, if at all possible. The card i'm looking at is a sapphire 100229L Radeon HD 2600XT 512MB 128-bit GDDR3 AGP card. I do have a agp slot so i know it will fit, but i am unsure if the GDDR3 is compatible with a DDR motherboard.