i just setup a windows 2008R2 standard server, with the only installed app being Hyper-V, and only 1 windows XP VM is running. Whenever i try to copy a file from my windows 7 laptop over to the 2008R2 server machine's admin shares ( \\servername\c$ ) the files start transferring around 60mb/s and then drop to around 5mb/s. My windows 7 machine and the server 2008 machine are both in WORKGROUP (no domain here). when i try the same transfer to our server 2003 box the transfer speeds are fine.

tried disabling autotuning (netsh interface tcp set global autotuninglevel=disabled)

as well as turning off the checksum offload to the adapter (tx and rx) - i still see strange packet errors (bad header checksum) using wireshark and just cannot seem to track down what the issue is - over 1 hour to transfer 4gb of files from 1 server to another that are on the same GB switch is just crazy....

any ideas would be greatly appreciated!


What happens if you shut down the XP VM? And if you remove the Hyper-V role altogether?

Alternatively, this could very well be a hardware issue; you can try changing the network cable, the switch port, and all else failing, the server's network adapter. Also forcing the connection to 100 Mbit instead of GB could help diagnosing what is going on.


What kind of computer is the Hyper-V server? How are the Hyper-V NIC, VM's NIC, and Virtual Switches configured?


when you add the hyper-v role to a server it makes a lot of changes to the host os, Microsofts best practice is to not install other roles on a hyper-v server because of this!

  • I would usually agree with this answer, as Hyper-V is well known for dramatically reducing hardware performance on the host in some scenarios (3D graphic cards); but it really shouldn't reduce network performance, which is a critical feature for a virtualization host. – Massimo Dec 28 '10 at 23:41

Try using a 3rd machine (the 2003 server) to copy the files from your laptop to the server.

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