Hi just signed up and have read through this old thread. I seem to be having a very similar problem of low transfer speeds across my home wired LAN:
one machine is running NIS2010 on WinXP Home 32bit (SP3), the other machine is running NIS 2010 on Win7 Home Premium 64 bit. They are both listed in each other's network map as being Fully Trusted.
Transfer speeds are very slow (between 15 and 60 kb/s) when trying to transfer files of any size, regardless of whether traffic is going through the Belkin 10/100 modem/router or directly through a brand new TP-LINK Gigabit switch (with both machines plugged into the switch rather than one into the router). I have even connected the two machines directly with a cross-over cable. Both machines have Gigabit ethernet adaptors.
The Windows Networking monitor thing shows it is using between 1.5 and 2% of the Gigabit capacity during the transfers.
The machines are physically close together and I have never had any problems with the cables being used.
I've tried disabling the Smart Firewall and Intruder Protection but it doesn't make any difference.
Help!!