MacBook very slow network (LAN) performance

Discussion in 'MacBook Pro' started by stcalvert, Oct 22, 2006.

  1. stcalvert macrumors newbie

    Oct 22, 2006
    I've got a week 30 2GHz Macbook running OSX 10.4.8. Up until today, the networking performance on this machine has been exemplary on both the wireless and ethernet interfaces.

    But now, suddenly (after no changes to the Macbook), I get pathetic transfer rates to other hosts on my LAN - like 60-70KB/s. It doesn't matter if I'm using the wireless or ethernet interface, the throughput is the same.

    I've tested the other machines on the network, and they can all communicate with one another at normal multi-megabit speeds over the wire or via wireless.

    I've cold booted the Macbook, did a tcpdump to check for heavy traffic, and checked the CPU usage (nominal). There doesn't seem to be any reason why this should be happening.

    Has anyone else experienced this? The only other problem I have with this Macbook (and it's a big problem indeed) is random shutdowns.

    Any help or insight would be appreciated.
  2. Queso Suspended

    Mar 4, 2006
    Have you made any changes to the duplex settings on either your network switch or the ethernet configuration on the Mac? Make sure both sides are set to Auto negotiation for speed and duplex.
  3. stcalvert thread starter macrumors newbie

    Oct 22, 2006
    The ethernet interface was set for automatic configuration, which selected 100baseTX full duplex (as reported by ifconfig).

    For fun, I manually configured the ethernet interface for the same settings (100baseTX fd), and applied it. My transfer speeds went back to normal, even on my wireless interface! What the...??

    I then switched the ethernet interface back to automatic configuration. Transfer speeds are still normal.

    Somehow, playing around with the ethernet settings got things corrected, even though I hadn't changed those settings in the first place.

    Oh well, at least it working properly now.

  4. terigox macrumors newbie

    Jan 25, 2006
    I wish I knew what you did! I still get poor wired transfer speeds with my MBP. I think I narrowed it down to just slow data transfer to it's HDD. But I'm not positive, this re-kindled some hope that it may be able to get faster :)

    I wish you found what exactly you changed! I'll have to play with some stuff tonight as well.

    Do you notice different transfer speeds across multiple files or when transferring single large files?
  5. Queso Suspended

    Mar 4, 2006
    Glad it's worked out. From the sound of that, it's highly likely it was a duplex mismatch, at least on the Ethernet. The Auto setting works by the Mac and the network switch negotiating a speed and duplex state between them when the connection first becomes live. If the Mac wasn't talking to the switch, the two sides of the connection would get different settings, meaning that TCP/IP would likely kick into a throttle back mode and retransmit packets a lot. By flicking the interface to a fully configured state and back you've kickstarted the Mac side of the negotiation into working again, which means the two sides are now set to the same speed and duplex.

    However, it doesn't explain the issue with the Airport. Maybe it was something to do with the binding of the IP protocol onto the interface drivers. :confused:

    terigox, what equipment are you using for the other end of that connection?
  6. terigox macrumors newbie

    Jan 25, 2006
    I don't want to thread steal! :)

    The symptoms he was having seemed similar to what I have seen, well, without the initial speed :)

    My "Top" speeds seem to be what stcalvert was complaining out as his bottomed out speed.

    I was trying to run my file copies through a Netgear gigabit switch and to a storage system which is running an AMD 3000, Debian Linux, and some SATA Samsung harddrives in raid1.

    I ran XBench again on my laptop today, and am getting

    Disk Test 27.59
    Sequential 31.07
    Uncached Write 41.97 25.77 MB/sec [4K blocks]
    Uncached Write 35.51 20.09 MB/sec [256K blocks]
    Uncached Read 30.33 8.88 MB/sec [4K blocks]
    Uncached Read 22.85 11.48 MB/sec [256K blocks]
    Random 24.80
    Uncached Write 9.51 1.01 MB/sec [4K blocks]
    Uncached Write 46.66 14.94 MB/sec [256K blocks]
    Uncached Read 53.64 0.38 MB/sec [4K blocks]
    Uncached Read 62.50 11.60 MB/sec [256K blocks]

    Does these sound like normal disk speeds? I mean, 1mb/s on unsequential writes??

    Let me know if you suggest starting a new thread so I'm not stealing :p
  7. Queso Suspended

    Mar 4, 2006
    Remember not to confuse 1MB with 1Mb. 25MB/sec translates to 200Mb/sec, so I don't see those write times as a slouch. However on RAID1 arrays, the read speeds are normally faster than write, not the other way round. What processes do you have running that could be influencing the performance? For instance, I know it's unlikely, but I don't suppose you have any form of anti-virus running on either box do you?
  8. terigox macrumors newbie

    Jan 25, 2006

    Those speeds are from my laptop (I'm not sure if I was clear on that), and I guess that is where my concerns were, as the server system seems quite a bit faster with disk access (makes sense considering they are 7200k drives). I'm trying to fish some comparable numbers out of the Linux system with bonnie.

    Neither system really runs much that would hurt it's disk performance, that I know of anyway.

    I was just worried my Macbook had horrible disk performance where others do not I suppose :)
  9. Queso Suspended

    Mar 4, 2006
    Sorry. You were clear, I just missed that bit. I think the laptop's HD is probably the bottleneck, but I don't think there's anything actually wrong with it. How big are the files you're transferring, and do they appear to be faster when copying from one direction than they are in the other?
  10. terigox macrumors newbie

    Jan 25, 2006
    I haven't tried copying in multiple directions actually, that would be interesting to try though *makes note to try when I'm back on the LAN* :)

    At the time I was trying to copy large files, between 1gb and 4gb I think, if I remember right. I had some video files that I was transferring them over to my "storage system" for permanent storage.

    Edit: I forgot to add I actually found and checked out some comparison scores from the xbench site at and the scores seem to be right around with what I got.

    I'm probablly just expecting too much from a laptop hard drive :p
  11. Queso Suspended

    Mar 4, 2006
    OK. Post back your results when you get a chance to try it.

    EDIT: Just saw your edit :). It's possibly the case, but it doesn't hurt to try it anyway.
  12. terigox macrumors newbie

    Jan 25, 2006
    I will, hopefully I'll be able to try it tonight. It's been a little while since I've moved stuff from my laptop for storage.

    A litlte late, but I'm also glad to see that you found a fix for your problem stcalvert :)

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