WIFI Signal Degrades More Than You Think

I recently went down the path of switching as many of my computers to gigabit ethernet and I wanted to test to make sure my cables were actually able to do 1000Mbit/sec. Unfortunately the normal route to do that is to buy a cable certifier unit that runs over $1000. But then I found iperf3, a linux/mac/win command line tool that can max out the network IO and tell you what it got.

That is when I realized it could give me actual wireless network speed instead of just transmitter rate. Now there are lots of potential bottlenecks with this setup — motherboard IO, NIC IO, my current radio airspace around my apartment, my router, etc. But it is interesting to see how a “realistic” apartment environment behaves with wireless signals.

Some notes of my setup:

The iperf3 server is running on an iMac that can local loopback 45000Mbit/sec (45Gbit/sec)
The iperf3 client is running on an Asus laptop that can local loopback 4300Mbit/sec (4Gbit/sec)
Over wired ethernet my router was able to switch 1000Mbit/sec between the laptop and desktop
My router is nothing impressive, it’s a D-Link DIR-860L running DD-WRT v24-sp2

You should not treat my results as a benchmark of all wireless setups but its interesting to see how it compares 2.4ghz wifi to 5ghz wifi at various channel widths.

2.4ghz Wifi N

advertised speeds are pretty unrealistic, according to my laptop and the router it is 144Mbps

5ghz Wifi AC

advertised speeds are pretty unrealistic
increasing channel width only helps nearby speed, far away spots will stay slow
going through 1 wall roughly cuts the speed in half

Want to run your own test?

You will need two computers – one to act as the server and one to act as the client.

https://iperf.fr/iperf-download.php (place the file into your path so you can call it by just iperf3 – on windows put it in C:\Windows and for linux put it in \usr\bin\ folder)

Server: