Reliable 25 Gigabit Ethernet via Thunderbolt

Summary

I stumbled upon this tiny Thunderbolt to 25 Gigabit Ethernet adapter on Amazon. It’s powered from the host, meaning there is only one cable, no additional power supply required. This is great for mobile setups and desktop work alike.The device comes in a nice travel pouch along with a rather short Thunderbolt cable. It is plug-and-play on macOS. Thunderbolt 25G Ethernet adapterYou can find the device under many names on Amazon (search for “thunderbolt 25G”). It comes in two flavors, single port and dual port SFP28, currently starting from $157. Most of its Amazon product pages don’t have reviews, and if they do, they’re mostly negative. I initially bought the dual port version at a good price, and later also obtained the single port version used in an even better deal.There’s no manual or manufacturer information; I assume it was put together by a small company in China (I found a corresponding offering on a Chinese b2b platform). On my MacBook Pro, the device identifies as “PX Thunderbolt to Ethernet”.All other 25 GbE adapter solutions I’ve found so far require an additional power supply, and either lack a proper case (like those cool Thunderbolt GPU dock setups) or have a spinning fan. I didn’t at all look at the ATTO ThunderLink or Sonnet Twin25G due to their obscene prices.With the obvious advantages of being absolutely quiet and not requiring an additional power supply, the biggest downside of the PX adapter is that it gets really hot, like not touchable hot.Sometimes, either the network connection silently disappeared or (sadly) my Mac crashed with a kernel panic in the network driver. Apple has assured me that this was not a security issue.Other than that, the PX seems to do the job: iperf3 reports a bitrate of 20.7 Gbits/sec (in one direction) and 8.4 + 17 = 25.4 Gbits/sec (saturated bidirectionally), approaching the practical limit for PCIe devices over Thunderbolt 3 or 4, which is in line with all other 25 Gigabit Ethernet/Thunderbolt adapters I’ve tested....