shaithis
Why call it a 2.5 slot card? Its a 3-slotter.
Well, you're right of course as there are no half slot cards, but I guess the thing might be if you two x16 slots with a 2 slot gap, then having a 2.5 would mean you'd get a half a slot of space. Since these are open cooler designs that might make a difference in that a 3 slot card would have less space to get it's air from.
EDIT: although that side shot photo makes it look more like 2.8 or so slots unless it's the angle of the shot.