Thanx for quick reply . My PSU is of 400W and I think it is enough for this graphic card because I have read that ATi 4000 series are compatible with low power PSU and my graphic card requirement written on the box is 400W. So the question is do I need to buy a new motherboard or I have to buy a new card. One more thing i want to say is that in the bios (when the monitor cable is plugged to onboard), under init display first only PCI and onboard are shown but my graphic card slot is AGP. Why?