Lets start with how Crossfire works externally. With SLi, you basically have to configure two things- first an SLI card between the two video cards needs to be setup in SLI mode and secondly, a bridge between the two cards needs to be connected. Once this is done, you boot into Windows, enable SLI and then reboot to put changes into effect. ATI wanted to make things less complicated with Crossfire. They somewhat adopted the old 3DFX Voodoo way of doing things and basically all that needs to be done is a cable connected from one card to the other externally and voila. There’s no need to reboot Windows either as Crossfire can be enabled or disabled on the fly.