Athlonxp2400
a friend with two 8x 8x cards and two ribbon has increments fps .. I with one ribbon to 2 did not change, but I have the cards to 16x 16 x ... I assume that the limit where they have increase with hb bridge is have the cards to 8x 8x
This doesn't sound like a carefully executed series of tests. interesting, but there are too many variables.
If it is true, then I presume that even in the 16x - 16x configuration that there is sli traffic taking place on the PCI bus, which isn't a good thing if you can get it off the bus. Any tests should take random load on the PCI bus from other devices to be closer to real-world example.