I just tried copying a file over cifs (windows file sharing) between a server 2003 R2 and a new server 2008 SP1 and I'm getting horrible speed.
it's a 300MB file that is taking around 30 minutes to transfer. I'm getting around 1-2Mbit/s and this is on a local switch.
I have tried initiating the transfer from both servers with the same results.
Copying from the 2003 to another 2003 is less than 1 min, so it's obviously something with the 2008-server.
An even weirder behaviour is that if I simultaneously copy another file from the 2003 server to another 2003 server, the transfer rate from the 2008 server increases drastically (like 10x times, but still slow though).
Over RDP-drivesharing I get full VPN-speed, approx 20Mbit. No other services seem to be suffering from any latency.
I have seen post about tcp offloading causing trouble in win2008, could it be related?