most H and B series boards doesn't support SLI, am i wrong?
all the boards I've seen with 2 slots with B/H chipset always have the second slot connected to the PCH (for 16/4 operation), so no SLI support...
it's funny because the board clearly have access to the full 16 lanes from the CPU, the same way the z boards, but maybe intel implemented some lock (like the overclocking one), or it's something else