After Apple released Apple Mac Pro EFI Firmware v1.3 on 3/27/08, the Sonnet Tempo SATA E2P card no longer worked in slot 2 of the Mac Pro Early 2008 Model 3,1. Slot 2 is a x16 PCIe 2.0 slot. The solution is to move the Tempo SATA E2P card to either slot 3 or 4, which are x4 PCIe 1.1 slots. The Tempo SATA E2P card works fine in the PCIe 2.0 slots in the Mac Pro (Early 2009) Model 4,1.
Using a Drobo S with a Macintosh and Sonnet Tempo SATA E2P, Tempo SATA ExpressCard/34, or Tempo SATA Edge ExpressCard/34. you may get a device removal error after waking up from sleep. The Drobo S will automatically reconnect. System caches are flushed before sleep, so there is not data loss.