Do you have a sleepy NIC?

@ Mike_O'Neill - The permanent fix would probably be a GPO/DSC (PowerShell 4.0's Desired State Configuration) setting that tells all NICs on the host to disable Power Saving; then you set that GPO on your Server Group(s).

Here's the Official Method to doing it, under 'Fix It Myself' it lists the Registry entry - there is one per-device, so one would need a way to enumerate all devices under that:

http://support.microsoft.com/kb/2740020

Here is someone who made a script to do it (his is set for Intel NICs only, but could be modified fairly easily):

http://community.spiceworks.com/topic/243073-we-need-a-gpo-or-script-to-adjust-power-management-on-nics?page=1#entry-2245885

community.spiceworks.com/.../243073-we-need-a-gpo-or-script-to-adjust-power-management-on-nics