I don't understand the decisions to use RJ45 copper cable for anything higher than 1GbE, unless

  a) You like small computers and these only comes with RJ45 ports and 0 PCIe slots
  b) You enjoy fighting with super rigid cables, port flaps and hot modules

I upgraded my home to full 10Gbps network at 2018. At that time:

  * 10Gbps SFP+ PCIe NICs (Mellanox CX3 and similar cards) are already dirt cheap ($15 for OCP adapted ones, $50 for native PCIe cards) because datacenters are upgrading to CX5
  * 10KM SM SFP+ modules are already dirt cheap (~$6) because 4G BBU-RRU communication uses these
  * Silent 10Gbps SFP+ switches start appearing (still a little pricey); 10Gbps RJ45 switches are not available anywhere

Those 10KM SM modules will happily run off <20m MM fibers so I just used whatever fiber I have at hand. The price is so cheap that I think the RJ45 upgrade path (2.5G has not been universal, 5G still very far away, 10G is so pricey) looks like a scam.

After 2024:

  * 25G/100G SFP+ PCIe NICs are dirt cheap (~$80 for single port 100G NIC)
  * 100G QSFP28 modules are in acceptable price; 25G SM/CWDM SFP+ modules area already dirt cheap (~$50 for 6-slot CWDM ones) because 5G BBU-RRU communication uses these
  * Silent 100Gbps switches start appearing (you can get 24*25G + 4*100G under 100W; still a little pricey); 100Gbps RJ45 switches are not available anywhere

I already have an experimental 6*25G CWDM fiber connection between my 2 rooms. Given that most of my devices wouldn't need anything higher than 10Gbps, I'm thinking of giving each room a single 100G port, split them into 4 lanes in the room with passive wavelength splitters for different devices, which further reduces cost on switches.