Are you expecting nearly line speed off the TMM node running as a guest VM? Eh, virtualized networking always extracts its pound of flesh (unless it's running an a virtual function off an SRIOV capable NIC, and most embedded NICs won't do SRIOV)..
There's not that many TMM nodes that can deal with SRIOV using a compatible NIC (Intel i350/710, Chelsio Terminator 5, Mellanox ConnectX3 or whatnot), and then you might still have to hack the Virtual Functions (VF) driver in. I think there's the Lenovo ThinkCentre P320/330 (the real estate is tight and you'll need to shoehorn card bracket support) or the HP t740, which is not really a TMM node, has limited SRIOV support (no PCIe ACS so limited to 7 VFs or less, and functional in Linux only).