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Weird file transfer speeds

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I've noticed that when I copy a file from computer A to computer B, the speed is about 3 MB/s. When I copy a file from computer B to computer A, I get 8-10 MB/s.

The files are large (multiple GB) so it is not as if I am dividing by a small time (leading to large error).

Computer A is a Windows XP machine. The HD is a RAID 1 array (using the mobo) of SATA disks.
Computer B runs Ubuntu (maybe 6.06?). There are multiple HDs, but all are IDE disks.
They are connected to a Netgear WGR614 v6 (a 10/100 switch).

Does anyone have any ideas what might be causing the difference? I am puzzled.

In a partial effort to earn a reply, I will try and post more details. I don't know what sort of info would be most helpful, so maybe someone could suggest a test to run?

Computer A's CPU is an AMD Athlon 64 X2 Dual Core 4400+. It has 4 GB RAM.

I ran iozone:
iozone -Rab [results file name] -i 0 -i 1 -+u -f file-on-ComputerB -y 64k -q 64k -n 64k -g 4G -z
and that showed about 9800 kB/s for reading and writing.
I don't really know what I am doing with iozone, running it or making sense of the output, FYI.
Let's see, two machines with different OSes and different drive setups. Your problem could be caused by lots of things.

1) How are you measuring the transfer rate?

2) Make sure your test file has been deleted from the machine that you are transferring (writing) to for each test to prevent cache effects.
Thanks for the reply; I really like your site.

1) In first post, I logged into Computer B from Computer A via an SSH program and then copy a file over.

2) I'm quite sure that's not happening; I will check again.
1) In first post, I logged into Computer B from Computer A via an SSH program and then copy a file over.
Hmm. Yet another set of possible causes.

I suggest you skip SSH and just do a drag and drop file copy from one machine to the other.

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