On my Windows 10 machine (10GbE wired, WSL2 Ubuntu), WSL2 networking was orders of magnitude slower than native Windows (KB/s–low MB/s in WSL vs full line rate in Windows).
The root cause turned out to be offload features on the WSL virtual NIC and the physical 10GbE adapter. Disabling them restored normal speeds.
- Windows 10:
10.0.19045.6466 - WSL version:
2.6.3.0