Graphics Eats Energy
This is the Radeon X800XL that we used for this article. Using any other current model would improve the 3D performance, but increase the power consumption maximum, while not improving the minimum power draw.
Using a reasonably powerful PCI Express graphics card instead of integrated chipset graphics is obligatory for running 3D applications and games, but this will add to the system power draw. We used a Radeon X800XL that would increase the system power draw by 20 W. Using any other recent graphics boards does not change the results fundamentally, because there is always a minimum power draw level. Faster graphics cards would also increase the maximum power drawn under graphics load.
Integrated graphics chipsets may have a handicap when adding a discrete graphics card. In the case of the MSI K8NGM-V, the power draw increased by 35% after adding the Radeon X800XL graphics card. This implies that the integrated graphics engine is not disabled automatically when a card is added; it keeps drawing power. There should be a BIOS setting to disable the integrated graphics unit when it is not required for multi-display setups.