Well I have Dell Dimension 4400 series computer that has an AGP 4x/2x slot, and also a 250 W power supply, I've been looking for video cards that have 256 MB of ram, specifically the Chaintech GeForce FX 5200, I would like to know if in general the AGP 8x are compatible with AGP 4x/2x and what is the minimum power that these cards run on?