The PCIe slots on the R310 are PCIe Gen 2 Slots, which the PRO1000 Quad Port is not compatible with. See this article: [URL] 
Latest BIOS 1.11.0 The card - Intel PRO/1000 PT Quad 4-Port PCI-E works (not faulty) It sits in Slot 2, yet it is NOT visible in BIOS (and ofcourse not visible in OS) Card in Slot 1, Broadcom NetXtreme II BCM5709 Quad Port shows/works fine  Any ideas if there are any issues with this unit?  Seb
R310 card in Slot 2 PRO/1000 PT Quad not visible