Bizarre download throttling issue. Mac OS related or wireless network related?

Discussion in 'Mac OS X Server, Xserve, and Networking' started by Jottle, May 13, 2013.

  1. Jottle macrumors 6502

    Oct 17, 2003
    I'm having a strange wireless bandwidth throttling issue that I hope someone on here might be able to help me solve. For some reason, all my downloads (for the most part) are no longer getting higher than 300kbps. I have a wireless n router/cable modem combo along with a cable internet subscription that nets me 18Mbps down and 10Mbps up. I've tested my connection multiple times throughout the day across multiple devices to ensure that I am indeed receiving the throughput I'm paying for. So I know the problem is not on my cable company's end.

    However, on my mac, whenever I download a file from a known high speed server (that should max out my connection) my maximum download speed hovers around 300kbps instead of something like 1.6Mbps where it should be. I know it's my computer that's the issue because if I attempt to download the same file off my roommates pc on the exact same wireless network connection, he gets the full 1.6Mbps download speed while mine just stalls at 300k max or just around that speed. The really weird thing is that when I do internet speedtests (e.g. in the various browsers on my mac, those report my full available speed (18Mbps down). The issue only appears on downloads, and it happens in every single browser I have installed. More curiously, these speed cap issues don't appear in my torrent program or within the steam application when downloading games, but they do appear in my browsers or through jdownloader download manager standalone application.

    It's as if my connection on my mac is capping itself out for some reason in browsers and download managers. I've disabled all proxies, any other programs that could be sucking up bandwidth (crashplan etc.), and all my browser extensions, but no matter what I still have these capped out download speeds in every browser. Any idea what I could do to troubleshoot this?

    I'm a fairly savvy mac user (10+ years), but this is baffling me. The only thing I can think of that makes my connection different from my roommate's is that I have changed my dns servers. Other than that, I can't figure out why my speeds are capping out when his download of the exact same link connected to the same wireless network is maxed out. Please help.

    2009 macbook pro: 2.8 c2duo, 8gb ram
    OSX Lion 10.7.5
  2. adamjackdrew macrumors newbie

    Jul 13, 2010
    I have to admit, I had witnessed similar in the past, although I don't now as (a) the connection ain't great at home, and (b) the iMac is the only main computer on the connection.

    Saying that, I have found the following page which may help.

    I haven't tried any of this, so can't guarantee how well it works. It may be worth a try though. I suspect firewall. :apple:
  3. Jottle thread starter macrumors 6502

    Oct 17, 2003
    Tried turning off the firewall. No luck. Anyone else have any ideas? if I bootup into bootcamp on the same mac, my speeds are completely high as they should be. So there's something going on on the mac os side of things, and it isn't an issue with my wireless card or anything.
  4. Jottle thread starter macrumors 6502

    Oct 17, 2003
    OK. More updates for anyone who can help out there. This is somehow related to my dns servers but also my web browsing. I figured out that if I change my dns servers, then I get fast downloads again as soon as I reconnect to my wireless. This is consistent. However, if I then browse the web a little bit, retrying those same known fast downloads leads to them being slowed to 200k If I disconnect and reconnect to my wireless network again, then my downloads are back to the higher speed until I start browsing to some pages again. So for some reason, my initial download speeds upon connecting to my network are good, but as soon as I put in some other http requests after those initial downloads, they then slow down upon retrying them. So the only way to fix this is for me to disconnect and reconnect my wireless again. This isn't a bandwidth issue b/c the downloads connect at the slower speed when there's nothing else using the connection. Can which dns server you use affect your download speeds?
  5. gnasher729 macrumors P6


    Nov 25, 2005
    Where do you get the numbers from? I haven't ever seen a Mac download displaying "Kilobit per second", but "Kilobyte per second" which is of course a much smaller number.
  6. Jottle thread starter macrumors 6502

    Oct 17, 2003
    Sorry, I meant kilobyte. I've pretty much established that disconnecting my wireless and then reconnecting will give me the faster (read full bandwidth) download speeds. But any browsing after that reduces any subsequent downloads via the exact same url to slower 300kbps speeds. Still can't figure this one out!
  7. WissMAN macrumors regular


    Jun 19, 2009
    Lone Star state
    Interesting observation compared to some of the more recent posts about wireless throttling.
  8. Jottle thread starter macrumors 6502

    Oct 17, 2003
    Anyone have any guesses on this? I'm completely stumped as to what would be slowing my download rates on the mac os side but not the bootcamp win 7 side. I'm being capped, but it's definitely not my isp. It has to be something installed on the mac os side.
  9. mwhities macrumors 6502a

    Jul 13, 2011
    Try reinstalling the latest combo update for your OS version?
  10. matspekkie macrumors member

    Oct 19, 2010
    Trash your wireless network settings

    First thing to try is to trash your wireless connection on your Mac.
    Then set it up new. Any garnalen dns / proxy Will then be gone.
    Hope That helps.

Share This Page