how to test imac wifi transmission speed

Hello:

I do not know of any program that will do that. There are, of course, programs to measure ISP speeds. What is it you are trying to determine?

Barry

Hold the ALT key then mouse the Wi-Fi menu item - current speed is listed under Transmit Rate.

Regards,

Shawn

Your Mac likely does not have an ALT key. Hold down the Option key on your Mac while you click on the fan shaped AirPort icon at the to of the Mac's screen.

The Transmit Rate will show you the theorectical maximum available connection speed in Mbps.

The actual throughput on the network will typcially be about half of the theoretical speed.

If you want to test your Internet connection speed, you can try a site like www.speedtest.net

I learned a lot about setting up a fast wifi LAN after I began streaming HD video from an EyeTV server. The streams would often stop and the obvious culprit was my bad network setup: I necessarily have a Time Capsule hidden away in a cabinet, and my main Airport Express router tucked away in another room next to the cable modem. It worked, but was slow with LAN speeds oftentimes under 2 Mbps (Mbits per second, not MBps == MBytes/s), with dropped connections if the signal level dropped low enough. Pretty bad.

Though it can be very helpful to look at the signal and noise levels reported by Airport Utility 5.6>Manual>Advanced>Logs and Statistics>Wireless Clients, the data rates reported by Airport Utility do not appear to be correlated with any achievable real-world bandwidths.

Instead, use iperf to measure speeds on the LAN, and curl or wget to measure speeds to the internet, as explained in this article [http://stackoverflow.com/questions/426272/how-to-test-internet-connection-speed- from-command-line].

I installed iperf on both server and client machines (e.g. from Macports: sudo port install iperf) and purchased the iPerf2 app for the iPad. For LAN speeds, make sure that you have iperf's port 5001 open on your server's firewall, then run iperf on both ever and client:

server$ iperf -s

client$ iperf -c 10.0.1.whatever_your_server_ip_address_is

For speeds to the Internet:

$ curl -o /dev/null http://speedtest.wdc01.softlayer.com/downloads/test500.zip

Note that curl will report speeds in kilo-Bytes per seconds, not bits/s.

On my LAN, I couldn't get the TC out of the cabinet, so I used a second-hand Airport Express as an antenna for the TC by setting it up to extend the Extreme's 5 GHz channel and running an Ethernet cable to the TC, which I put in bridge (repeater) mode. Then I mounted the Express high on a wall, away from everything else. Alternately, you can wall mount the wifi router for best performance. I also made the mistake of positioning the wall-mounted Express within an inch of a room corner, just the worst spot for a corner reflector dead zone at wifi's 2.4 inch wavelength = 3e8/5e9*100/2.54. Moving the Express out of the corner dead zone by a couple wavelengths ~= 5–6 inches made a huge difference in signal level and speed, and in general you need to worry about difficult-to-predict shielded zones all over your space. You just have to test it.

Bottom line: by using 5GHz with wide channels and wall mounting an access point with good positioning, my LAN speeds went from under 2 Mbps to 40 Mbps measured on the iPad using iperf with TCP, and even higher speeds with UDP.