[jburgess777]

I think the point he is making is that the industry first went with a 10g single link, and then 40g over 4 links. Then they figured out how to do 25g over a single link, and 100g over 4 links. Those 25g/100g are common for enterprise switches. It might be fairer to say 40g is dead, 10g still has use cases.

Edit to add: If you want an example, these are the NVidia ConnectX nics available from FS.com, the lowest end one is 25g, then 100g, 200g etc.

https://www.fs.com/uk/c/nvidia-ethernet-nics-4014

[namibj]

What they mean is that the cost per bit both capex and opex/power is worse for 10G than 25G for a while now as long as you talk about new hardware.

We're at the point where 25GBaud PAM4 is being replaced by 50GBaud PAM4. That's 50 to 100 Gbit/s.

But iirc the use of PAM4 for the faster ones than "only" 25Gbit/s lanes is a hindrance to managing bottom-barrel price-per-bit. PCIe 3 was 8, PCIe4 was 16, and PCIe 5 is 32 GBaud with a line code basically like the 10+ Gbit/s Ethernet links (well, it's 66b/64b for Eth and 130b/128b for PCIe).