[Wylug-help] Rsync is broken?

[RichardA]

For a while I've run a script at boot which has rsynced /home (230GB)
with a 'server' (a low profile mini-itx box, actually). Now it doesn't
work, and I can't for the life of me work out why.

Some background: I replaced a 10MB NIC in my desktop PC for a 100MB
one, and soon after noticed that the backup script wasn't working.
When I run it manually it fails after a few GB of traffic with an
error like this:

-------------------------------
Received disconnect from 192.168.1.2: 2: Corrupted MAC on input.
rsync: writefd_unbuffered failed to write 16385 bytes [sender]: Broken
pipe (32)
rsync: connection unexpectedly closed (57786 bytes received
so far) [sender]
rsync error: unexplained error (code 255) at io.c(454)
[sender=2.6.9] root at cetri ~ #
-------------------------------

Googling the error showed problems with Realtek NICs or bad memory. I
have swapped NICs on both server and desktop a number of times, I've
swapped out two memory sticks in the server, the OS on the desktop has
been reinstalled for unrelated reasons, I tried using an old 10MB hub
to connect the PCs in case my Linksys router was corrupting packets..
but nothing has helped!

I've run out of ideas, does anyone have any idea what the problem could
be, or how I could troubleshoot it?