I'm about to build an 1155 rig and I am waiting, like everyone else, on the restocking of the 1155 boards. I plan on buying one of the ASUS offerings and was trying to decide which one to get for my dual gtx 560's. All of their 1155 builds say "quad gpu support" but how is this possible with only 2 pci-e slots? Am I misunderstanding how quad gpu setups work? I've only ever dealt with SLI boards.
Off of the top of my head I would say it's because it can run two dual-GPU cards, like HD 6990s or HD 5970s, while dual CrossfireX would only allow for a single dual-GPU card. I'm not sure of that, but that's my impression.