Actually if you have cat5 or cat6 base-T setup, you can get second hand dual port 10gbe pcie cards for 30 dollars each(!)
10GbE baseT switches are more expensive than fiber equivalent though.
10GbE baseT switches are more expensive than fiber equivalent though.
ime if your unloaded latency on copper ethernet exceeds 0.2ms per hop there is some form of powersaving involved
SPF+ switch to OM3 fiber to SPF+ PCIe card => 0.2ms
SPF+ switch to RJ-45 cable to RJ-45 PCIe card => around 3ms
Some advice: make sure you know the form factor of your NICs. I accidentally bought FlexibleLOM cards. They look suspiciously like PCIe x8, but won't quite fit. FlexibleLOM to PCIe x8 adapters are cheap though.