On my 2009 MacPro, I've tracked down an issue with PCI Slot #2, where it drops ACHI devices while in sleep, upon resume the devices are lost and no longer available to the system. boot devices hang the OS. external devices are ejected and remounted fresh install of 10.9.0, updated to 10.9.1 100% reproducible with SATA Express, USB3 controllers. I've reported this issue to Apple in the past, and they blamed the device manufacturer. This appears to be an issue isolated to slot #2 and not a result of a an individual product. Anyone else have any issues with Slot 2?