I bought a bunch cheap HP 40Gbps NICs [0] when they were $13 but need PCI-E risers to make them fit a full height slot. Work fine in pfSense & Fedora.
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Oh, if you have even a hobby grade CNC machine around, you can get a fairly professional level result:
https://forums.servethehome.com/index.php?threads/3d-printab...