There’s an easy way to test your Internet connection speed from the Terminal Command Line.
1. Open Terminal.app (use Spotlight if you don’t know where to find Terminal.app
2. Paste the following command into the command line:
curl -O http://speedtest.wdc01.softlayer.com/downloads/test10.zip > /dev/null
You’ll see the download speed, and average download speed. The output in Terminal will be something like this:
% Total % Received % Xferd Average Speed Time Time Time Current
Dload Upload Total Spent Left Speed
100 11.0M 100 11.0M 0 0 730k 0 0:00:15 0:00:15 --:--:— 742k
"Average Dload" is the average download speed.
If you'd rather use a pretty interface in your browser, you likely already know about www.speedteest.net