Pci-e switches between 1.1 and 2.0 bus?

[Mars999]

I have just put together a ASUS P8P67 Deluxe, Core i7 2600k system, with Geforce 560Ti rig. For some reason my PCI-e bus switches back and forth between 1.1 and 2.0? Is this normal? And if so is it for power saving? How can one change so it doesn't switch but stays locked at 2.0...

Thanks!