I don't think this board is XL-atx, looking at the mounting holes it looks like SSI-CEB, just a bit bigger, so it should fit where an eatx board will, but the last slot in 4x sli/xfire will need a chassis with 8 slots. I could be wrong but it looks just a tad bigger then the p6t7 ws but not as big as the evga 170-BL-E762-A1.
Now the real question is where are the full specs and when can we buy it !!!