Currently, there's a bit of monopoly for nVidia with SLI and the nForce4 chipset. There are some others beginning to emerge from various producers, including ECS and Sapphire motherboards with Radeon chipsets [url=http://www.tomshardware.com/hardnews/20050828_231427.html]and now Intel, getting ready to release boards with their souped-up 955, dubbed the 975[/url. This chipset will supports dual x16 GeForce cards, and is going to debut with the release of the Pentium 4 D 900. There isn't any information yet on whether or not Crossfire (ATI's solution to multi-GPU) will be supported, but knowing Intel, it will be supporter or an alternate would be soon available. The new chipset is supposed to outperform, marginally, the 955, though the real attraction here is SLI. As with all Intel boards it will come at a price, especially with Intel axing their entry-level chipset line.