To clear things up a bit, PCIe 2.0 is a revision of 1.1, that allows more power and bandwidth to go through the PCIe slot. X16 is the amount of bandwidth that the PCIe slot is capable of.
The 680i chipsets do not support PCIe 2.0, but it's PCIe 1.1 slots, are capable of using x16 bandwidth.
The X38 chipsets do
support PCIe 2.0, and it's slots are also capable of x16 bandwidth.