Top two card slots are X16 and the bottom is X8
With 2 cards in the top two slots both work at X16
With three cards in Top X16 second and bottom slots X8
Only so much bandwidth on the slots
He can still crossfire the 16x with the 8x without a real performance loss, right?
Still though, crossfire bridge probably wouldn't reach. Haven't seen too many 16x16x8 mobo's, probably because there aren't many on AMD's side at newegg.