Originally Posted by cadaveca
BTW, it's not just the switches, SLI support in BIOS also plays a role in PCIe 3.0 support. Boards without SLI, all support PCIe 3.0; P67, H67, Z68, Z75, H77, Z77 all inclusive.
Actually, SLI doesn't have too much to do with this.
If there are no PCIe switches between the CPU and the card, the card will run at it's maximum speed, in that case GEN3.
I think you're referring to the fact that SLI NEEDS
switches on 1155 to operate (it requires x8 traffic, for both GEN2 and GEN3), otherwise you'd be stuck with a fixed configuration 8x8 board. The switches are there to redirect the traffic to the first card in case the clockgen in the PCH doesn't detect a card in the second slot.