Strangely Slow Powerline Speeds

[Peteman100]

I use Zyxel PLA-401 AV200 powerline adapters to connect a router on the second floor of my house to my downstairs router. I get fairly slow speeds (<10Mbps), because the connections points are far from each other. I bought a newer set of Zyxel PLA-5456 AV2000 adapters, hoping to see at least a 2X improvement. In the course of doing speed tests to compare the models, I found a strange problem.

During file copy tests between both sets of adapters, the best speeds I saw were 7Mbps write and about 70 Mbps read. This is when the pairs were placed in outlets next to each other. Literally no difference between the old AV200s and the newer AV2000s. Am I missing something? Why are my power line adapters so slow, even when placed next to each other?

 

[ColinTaylor]

Install the "ZyXEL PLA Series Configuration" utility and with the adapters plugged into adjacent wall sockets, see what link speed the utility says you have between them.

With my 2 PLA4201's plugged into adjacent sockets I get a link speed of over 300Mbps. From the 1st floor to the ground floor I get about 150Mbps.

Obvious question: You are plugging them directly into the wall sockets aren't you? You're not plugging them into an extension strip/block.

 

[thiggins]

And did you unplug the old adapters from power when testing the new adapters?

If you connect the two computers you are using to test throughput via Ethernet, what do you get?

You could also have noise sources. Small power adapters like cellphone chargers will knock down throughput.

 

[sfx2000]

LED lights can also be a significant noise source when on....

 

[Peteman100]

Thanks everyone. I unplugged my old power line adapters and every plug in the room before running the test. Will noise sources anywhere in the house have an effect or only locally to the plugs? I also don't have LED bulbs.

I gathered more data. Using the Zyxel utility, the link speeds are 1453 Mbps transmit and 1678 Mbps receive (see below), so that doesn't seem to be the issue. Even still, I'm only getting 10Mbps write and 77 Mbps read (see below). Directly connecting the computers, I get 40 Mbps write and 90 Mbps read.

 

[ColinTaylor]

Can you test the speed using something other than a Samba share on OSX? You might be seeing an issue with the computer rather than the network.

iperf perhaps?

 

[Peteman100]

Colin, you were absolutely right. Using iPerf3, the new powerline adapter was saturating my 100 Mb/s ethernet plug where the old set only managed 43 Mb/s. I'm pretty happy with that result! Thank you all for the help!