PCI Express 2.0 AIBs are not compatible with non-2.0 mainboards

X-bit Labs have asked the PCI-SIG for clarification on whether upcoming PCI Express 2.0 AIBs will work correctly in mainboards that only support PCI Express 1.x. The answer, that, "new PCIe 2.0 adapters running at 5.0 GT/S can plug into existing PCIe slots and run at the slower rate of 2.5 GT/S", was expected. What […]

X-bit Labs have asked the PCI-SIG for clarification on whether upcoming PCI Express 2.0 AIBs will work correctly in mainboards that only support PCI Express 1.x.

The answer, that, "new PCIe 2.0 adapters running at 5.0 GT/S can plug into existing PCIe slots and run at the slower rate of 2.5 GT/S", was expected. What wasn't so expected was the article reporting that ASUS have warned that PCI Express 1.1-compliant slots might be required, and that 1.0/1.0a slots might not support the standard.

"It turns out that Asus Blitz mainboards based on Intel P35 chipset and using a special CrossLinx chip to support “PCI Express x8 + PCI Express x8