I have done a clean install upgrade on a Dell Poweredge R420 from Server2008R2 to Server2012R2 Hyper-V but my data transfer over the LAN is struggling. Before the upgrade I was able to transfer at around 111Mb/sec. Now, it will start out at around the same 111Mb/sec but after a minute or two it drops down to an average of around 15 - 20Mb/sec. Some research has recommended updating the drivers on the Broadcom NetXtreme NICs to the latest. I have done so but no improvement. The only thing I can think of is that I have my 2 NICs in a teamed LAN setup. I am thinking of unteaming them to see what the speed is like on a single NIC (in the middle of a large VHD transfer at the moment so can't try it yet). I've also updated the PERC controllers firmware and drivers just in case.
It's definitely a software issue as I was able to transfer off the same hardware prior to the OS upgrade with no issues.
Just to be clear I am transferring from one LAN host to another, there are no VMs involved at this point.
No AV on the host either.
Any suggestions would be very welcome.