Too many rumors over all of this.
First of all we were told that Ivy Bridge would work in P67/Z68 mobos but without PCI-E 3 support.
Then Gigabyte come out and "officially" announces a BIOS update which makes all thier P67/Z68 boards PCI-E 3 compatible. Now they are saying they only meant that it would only enable the use of PCI-E 3 devices and not make them fully PCI-E 3 with PCI-E 3 bandwidth. The thing is they didn't say that is what they meant when they announced the BIOS update and it sounds to me like it's a cover story to cover their backs.
And now finally we are being told that Ivy will not work with P67/Z68 anyway because of UEFI.
As for MSI not having any PCI-E 3 devices to test their mobos on and disprove Gigabyte, the IGP on the engendering sample Ivy Bridge CPUs they have might be PCI-E 3 which would make sense seen as they have a PCI-E 3 controller and the fact that we now know (or do we?) that we will need a gen 3 mobo to use them.
I'm waiting till we have solid facts and or benches before I listen to anything about PCI-E 3 compatibility and what motherboards Ivy will or will not work on.