Wi-Fi vs Ethernet for file transfers

For large transfers, the number printed on a Wi-Fi connection or Ethernet port is a link rate, not a guarantee of file-copy throughput. Ethernet is usually more predictable, while Wi-Fi performance changes with radio conditions.

Why Wi-Fi varies

Distance, walls, interference, channel width, access-point load and other wireless clients all affect usable throughput. Upload and download performance can also differ.

Why Ethernet is easier to plan

A wired link normally provides a more stable path. But a 1 Gbps Ethernet connection still has a theoretical ceiling of 125 MB/s before protocol and application overhead, and storage can become the next bottleneck.

For NAS and backups

If predictable completion time matters, measure sustained throughput on the real path. Use that measured rate in the transfer calculator rather than assuming the advertised link rate.