Why is my connection to the internet so slow across a wireless Airport network on the Mac?

Martin Cook May 6, 2011
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Why is my connection to the internet so slow across a wireless Airport network on the Mac?

  1. Tina
    May 8, 2011 at 6:57 pm

    Martin,

    were you able to look into the possible causes of your slow connection? Please let us know in case you were able to fix it!

  2. Mike
    May 6, 2011 at 6:59 pm

    There are various factors which might slow down your AirPort speed:
    - the used WiFi standard (802.11a/b/g/n)
    - signal strength
    - other users and computers using WiFi

    For the first one you will have to look up what mode is supported by both, your AirPort card on the Mac and your Router.
    Theoretical speeds are 11Mbit/s for 802.11b, 54Mbit/s for 802.11g and 802.11a. As for 802.11n it depends vastly on the implementation but mostly they are stated with 300Mbit/s. In reality these speeds are much lower for example a Wireless-G with good signal strength is usually around 24-36Mbit/s.

    Since file transfers are measured in MByte and not Mbit we have to convert them. Let's say your network is running at 36Mbit/s your maximum transfer speed will be ~3.6MByte/s

    Before anyone starts complaining that 1Byte = 8bit here is the answer: Overhead. For example each packet has at least 1 start bit and 1 stop bit, hence I calculate with 10.

    For the signal strength you can either alt + click the AirPort symbol (10.6) or you can use a tool like iStumbler http://www.istumbler.net/

    The tricky thing about WiFi is that you are actually looking at a shared bandwidth. Again for Wireless-G this means if you have 10 users on your WiFi you don't have 10x54Mbit. You got 54Mbit for 10 users! If only five of them are doing some YouTube watching there will be almost no bandwidth left for anything else.

    The options to improve speed are simple and limited:
    - change to a faster WiFi standard (again, has to be supported by all devices)
    - improve signal strength by changing location and/or eliminating interference e.g. wireless phones, mobile phones, other electronics
    - use cable connection whenever possible, don't connect everything via WiFi just because it's so easy

    Another option would be to setup additional Access Points, secondary WiFi Networks or something but this is another topic.