Powerline adapters are great for spreading Ethernet throughout the house without running cables through walls or along floors. Yet there’s a commonly overlooked factor I’ve noticed when people select them. It’s do to with the advertised speeds the adapters are capable of.

TP-Link are a common vendor of such devices, let’s take a look at a couple of units available in the UK:

Powerline 600 Wi-Fi Powerline Extender

You’ll notice that the marketing advertises this device as capable of 300mbps:

Extend 300Mbps wireless connections to previously hard-to-reach areas of your home and office

While technically true, it doesn’t highlight very well a key piece of information; The device ships with 100mbps ethernet ports. So while the powerline connection between units could reach a theoretical 300mbps, the output of each unit will never exceed 100mpbs.

This happens on Gigabit units too:

AV1300 Gigabit Passthrough Powerline ac Wi-Fi Kit

This unit is advertised as reaching speeds of up to 1300mbps between units. Again, while true – it ships with Gigabit ethernet ports limited to 1000mbps. The extra 300mbps will never be seen by clients.

So remember to take this into account when purchasing Powerline adapters. The two most common ethernet adapter speeds these units ship with will either be 100mbps, or 1Gbps. Anything above those speeds will go unnoticed.