Is Geforce 9800GT 512MB DDR3 compatible with the ASUS P5VD2-X motherboard?
Yes, the card is compatible with your system just make sure that you have a decent power supply at least a 500 w and above. If your power supply is not good enough consider Radeon HD 6670 its much faster than Geforce 9800 same time consumes almost half of Geforce 9800's power! and is fully DirectX11 complaint.