The maximum wired speed supported by the adapter.
When choosing according to this indicator, note that manufacturers usually indicate the theoretical maximum in the specifications. In fact, the wired speed can be noticeably lower (in particular, due to interference in the mains). In addition, it may be limited by other factors: for example, if the adapter has only one 100 Mbps Fast Ethernet port, then its actual bandwidth cannot exceed 100 Mbps, even if the specifications indicate a wired speed of 500 Mbps .
Nevertheless, the higher the claimed speed (
1 Gbps), the higher the practical one, all other things being equal. So for tasks related to the transfer of large amounts of data or requiring a quick response (watching/broadcasting high-definition video, working with torrents, online games), you should choose the “faster” models.