Network Adapters, RJ45 Plugs and Couplers

USB, PCIe or Wi-Fi for your network adapter?

Match the adapter's speed to your network. Wired adapters are labeled by speed, such as Gigabit, 2.5 Gigabit or 10GBASE-T, and the port and cable category must support it: Cat5e carries Gigabit and 2.5 Gigabit, while 10 Gigabit needs Cat6A for full distance. USB adapters need a USB 3.0 port to reach Gigabit and above, and PCIe cards need a free slot with enough lanes. For wireless, check the Wi-Fi generation, such as Wi-Fi 6, and whether your router supports it.

The small parts that limit network speed

RJ45 plugs are made for a cable category and conductor type: solid or stranded, shielded or unshielded, and standard or pass-through. A plug meant for Cat5e will not do justice to Cat6A cable. A female-to-female coupler joins two patch cables but adds a connection that can lower performance. Passive Ethernet splitters must be used in pairs and usually limit each link to 100 Mbit/s, so they are not a way to share one Gigabit port. For several devices, a small switch is the dependable choice.

Questions about Network Adapters, RJ45 Plugs and Couplers

Is a USB Ethernet adapter as fast as the built-in port?

Gigabit and 2.5 Gigabit USB adapters can match a built-in port when used on a USB 3.0 or faster port. On a USB 2.0 port they are limited well below Gigabit. Check that the adapter's chipset has drivers for your operating system too.

Will a Wi-Fi 6 USB adapter give me Wi-Fi 6 speeds?

Only if your router also supports Wi-Fi 6 and the adapter is on a USB 3.0 port. Real speed depends on signal strength, the number of antennas and the band you connect to, so expect less than the headline rate on the box.

Do I need Cat6 cable for Gigabit?

No. Cat5e carries Gigabit, and also 2.5 Gigabit, over normal runs. Cat6 supports 10 Gigabit over shorter runs, around 55 m, and Cat6A holds 10 Gigabit to the full 100 m. Choose by your speed target and run length.