AirDrop cuts WiFi speed from 300 to 144Mbit/s

Discussion in 'Mac OS X Lion (10.7)' started by Greendave, Aug 7, 2011.

  1. Greendave macrumors newbie

    Jun 9, 2008
    Tests: 2 x MacBook Pro on SnowLep WiFi to Airport Extreme run speed 300Mbit/s - upgrade to Lion then they run at 144Mbit/s.
    2008 iMac (not AirDrop capable WiFi card) using Lion runs at 300Mbit/s to same Airport Extreme until MacBook Pros start using same Wifi and then iMac drops to 130Mbit/s. Using Airport Extreme "guest network" feature to swap the iMac to separate WiFI network speed returns to 300Mbit/s.

    Conclusion: Airdrop on the MacBook Pros sets up its own WiFi network using half the card's resources and drops the main WiFi link speed in half. Do not understand why iMac speed on same WiFi network drop to half when MacBooks with Airdrop are used.
  2. The pSYION macrumors newbie

    Aug 7, 2011
    Are these actual values or are they like the connection state? Does seem very strange indeed! I have read in many places that even the N Standard can't reach 300MB/s in most cases so maybe the Macs are just realising this on the new software in a way they didn't before?

    Not the most technical answer LOL, have you tried transferring files on both setups to see if the actual speed is any different?
  3. revelated macrumors 6502a


    Jun 30, 2010
    I'm given to understand that AirDrop is a secure "tunnel" that is created between the computers connected. If that's the case then it's entirely possible that it is creating some sort of limited VPN strictly for the purposes of file transfer. Secure sockets always affect total connection speed because each packet is set encrypted, just by being connected to the tunnel. The only way to get around that would be multiple network adapters - one secure, the other not, and use traffic shaping to send certain packets to given adapters based on the source application or data.

    A theory only, based on what I know of VPN.
  4. Greendave thread starter macrumors newbie

    Jun 9, 2008
    Network monitor link speed readings

    The speeds refer to the link not the throughput. When using Lion, Airdrop is on by default and this establishes an independant wifi network which I have not yet worked out how to monitor. The effect on the wifi network established by the Airport Extreme can be seen by using Network Monitor (in your utilities) and selecting wifi. The link speed is reduced by approx 50% when using lion on an Airdrop capable machine - and you cannot disable Airdrop!!!!
  5. Celeron macrumors 6502a

    Mar 11, 2004
    Hmm. I have two 15'', 2010 Macbook Pros. Both have Lion installed via a clean install. Neither one is reporting a 150mbps link speed to either of my two, 4th generation, Airport Extreme base stations. Each one is showing the expected 300mbps link speed.

    Regarding AirDrop. It sets up a point to point network. However, this link is only active on my laptops when I select AirDrop from within Finder. You can see this point to point link in the CLI, "ifconfig". Its "p2p0" on my laptops. A Wireshark capture on that interface shows no traffic until two laptops are:

    1. Within range of each other


    2. Both laptops have selected AirDrop from the Finder window.

    Sorry, but my data doesn't support your conclusion.
  6. phyrexia, Aug 7, 2011
    Last edited: Aug 7, 2011

    phyrexia macrumors 6502a

    Sep 3, 2010
    I cannot comment on the fact that your MBPs only connect at 144 now.

    However, when a wireless router has two or more wireless clients with differing speeds, it will run the entire network at the lowest speed. This is normal behavior. This is why I have a WRT300N for my N networks and a WRT54G for my B/G networks. I did a good bit of research on wireless networks about a year ago when I moved.

    The iPad only connects to N networks at ~60mbps on purpose, for battery purposes. Is there a power management setting in Lion to check out? Maybe the OS is throttling. Or if you can turn off AirDrop like others have said, maybe that will help.
  7. Greendave thread starter macrumors newbie

    Jun 9, 2008
    That's interesting guys. Wifi network slowing to lower client makes sense. However Celeron's tests leave me with a problem. I have now upgraded 3 MacBook Pros to Lion. All three were running at 300 before upgrade and then 144 after installing Lion. (2 are Core2s from USA and 1 is a brand new uk i5). Celeron's results mean I have a problem with my setup. Only thing that comes to mind is I am running 2.4ghz because 5ghz drops and hangs in my 350yr-old house. Could be the problem is just on a 2.4ghz network. Still odd that my iMac which can't run airdrop connects at 300 yet the upgraded MBPs now only run 144 but did run at 300 tested immediately prior to upgrade and on the same network in the same location.
  8. Celeron macrumors 6502a

    Mar 11, 2004
    I should clarify, I'm running on 5ghz. I haven't tested 2.4ghz. If you enable 5ghz and then go within range of the AP are your results the same?
  9. Greendave thread starter macrumors newbie

    Jun 9, 2008
    Will try the 5Ghz and do some tests tomorrow - but problem remains on 2.4Ghz. Still no idea why MBPs slowed from 300 to 144 immediately after installing Lion. Will post 5Ghz results.
  10. phyrexia macrumors 6502a

    Sep 3, 2010
    OP, are your laptops running clean installs as Celeron or are you upgrading your systems?
  11. Greendave thread starter macrumors newbie

    Jun 9, 2008
    1 x MacBook clean install 2 x upgrades - all same symptoms of WiFi dropping from 300 to 144 on 2.4 Ghz Network.

    Tried on 5Ghz and link speed on MacBooks back up to 300 but no increase in throughput speed and also unreliable even with 3m distance to base station.

    Guess I'm just lucky to have 3 MacBooks here which all dropped in link speed upon install of Lion.

    Going to give up worrying about this unless someone else has the same symptoms when the upgrade and they are running a 2.4Ghz network.
  12. soopahfly, Feb 11, 2012
    Last edited: Feb 17, 2012

    soopahfly macrumors newbie

    Feb 11, 2012
    Same(?)problem, but was able to improve

    I had the same problem: After installing Lion, my Late 2008 MBP was unable to connect to equally old Airport Express base stations with a 300MBit link. My Airport Expresses are the older ones which are not capable of using 2,4GHz and 5GHz in parallel.
    After Lion, not only was I unable to connect with more than 144Mbit, also the general transmit speed was a lot less than you'd expect=> From before 8MB/s (even with less than a 300Mbit link) to now around 3.5MB/s.
    I also expected Airdrop to be part of the problem, as I was able to see with a scan that Airdrop sets up an independent 144Mbit always on network in the 5GHz band.
    I went on to disable Airdrop (the whole service). Airdrop gone, but Airport Express still limited to 144MBit.
    I have two Airport Xpress and a Fritzbox Router. Funny enough, the same MBP connects happily via 300Mbit/5GHz link to the Fritzbox, even post Lion. My standard setup, which worked great pre-Lion was to use the two Airport Xpress base stations to have 2,4GHz Wifi (between 144MBit and 300Mbit link) all over the house, and the Fritzbox to have a small 5GHz bubble (300MBit link, less crowded) around my office. As I mentioned, with Snow Leopard this would give me 8MB/s as a minimum all over the house in both bands.
    It should be mentioned that even before, the only way to actually get 300Mbit out of the Airports was to change the country code to a few select countries, e.g. Ireland for 2.4GHz or e.g. Norway for 5GHz.
    I used the Lion Wi-Fi Diagnostics tool to check out what was happening. The maximum transmit rate for the Airports (2.4GHz) was 130mbps, but the actual data speeds were much lower. Conversely, the average transmit rate of the Fritzbox (5GHz) from where I was testing was much lower (87mbps) and data rate was still over 8MB/s. I noticed that the country code shown was always AT, even though I had Ireland in the Airports. I reconfigured the country code in the Airports to CZ (update only possible if you change something), reconnected, Country Code shown was CZ, data rate went immediately up. But, after a while, the Country Code displayed changed to AT again - data rate dropped by 50%. The Fritzbox sends on channel 108 - that is not allowed in Austria (AT). This could explained why I would sometimes get a timeout when trying to switch networks. I have no clue who introduces the wrong country code (might be the Fritzbox, might be a neighbors network and it happens when scanning networks), but changing the country code of your computers airport card / base station drastically affects the wifi data rates possible with this type of Airport Express (Firmware 7.6.1), independently of the shown link speed - under Lion the MBPs airport card country code is collected automatically from the base station - at least in my case that leads to trouble. What I did is I moved the Airports SSID on top of the preferred connection list for the computers that typically have to go through the Airport network and deleted the unnecessary one. For now, this keeps the Country Code set to the one configured, which keeps my data rate high. Sounds like Voodoo, but works for me.

    Update: It's the Lion Wifi Driver. It has bugs/problems (as of 10.7.3, at least with Broadcom chipsets). I downgraded to the 10.6.8 Snow Leopard driver. Kills Airdrop for good, but got rid of my general speed problems. Airport Express still only good for 144Mbit links though. I saved the IO80211family.kext from my Snow Leopard installation and installed in Lion with Kext Utility (just drag onto the window).

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