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I wanted to transfer files between two mac computers. The network is wireless-N and both computers have wireless-N modules in them.

The problem is that when I transfer files between them, via file sharing (afp) the network speed caps at 2 megabytes/sec. Just downloading files from the internet I can get faster speeds, so this isn't a constriction of my wifi bandwidth, it appears to be a constriction of the protocol being used.

My wifi-n is set to 130mbits, so I should see real world transfer speeds around 12-16 megabytes/sec

I did this command on both computers sudo sysctl -w net.inet.tcp.delayed_ack=0 which is supposed to lower tcp overhead, but this did not affect it.

How can I get the speed I am expecting?

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up vote 1 down vote accepted

12-16MB/s real-world over a theoretical 130Mbps connection is a pipe dream. Air waves around my place are so congested in the 2.4GHz range that my Wifi-N (theo. 300Mbps) can barely manage 25Mbps of actual throughput, and is surprisingly slower than my internet connection. Theoretical speeds are just that, and sadly wifi only often sees a small fraction of them. (I've found myself in practice to be able to get much closer to theoretical speeds via wired networking, presuming you have a harddrive array that can keep up)

If you can get faster speeds via internet downloads, then did you try using FTP to transfer the files between your computers? FTP generally has very little overhead, and will give you a good example of your network capacity presuming that your harddrives aren't the bottleneck (they shouldn't be at these speeds).

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I haven't tried FTP or wired connection yet. I am a bit disappointed in the outcome of 802.11n, I will have to check again to see if I am using the 2.4ghz band or the 5ghz band – cqm Jun 19 '12 at 16:22
having one computer on wired did help. My throughput averaged at 6 megabytes a second. which was very tolerable. The file transfer time went from a theoretical 7 hours to a theoretical 2 hours. – cqm Jun 22 '12 at 20:24

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