Questions about Ugreen External Adapter Gigabit Ethernet USB 3.0 (grey)

Yes, this USB 3.0 Gigabit Ethernet adapter is compatible with Ubuntu and other Linux systems, but it may require installing drivers for Linux kernel versions 4.x, 3.x, or 2.6.x. The manufacturer provides instructions for driver installation on Linux, indicating it is supported though not always plug-and-play without driver setup. It works with Linux kernel 3.x/2.6 and above, so it should work with Ubuntu distributions using these kernels or newer.

The network adapter in question has a maximum speed of 5000 Mbps, but it is limited by its Gigabit Ethernet technology, which does not exceed 1000 Mbps. So even if your internet connection is 2.5 Gbit/s, the adapter won't be able to exceed 1000 Mbps.