Recently I implemented a brand new, very powerful server with solid state disks running Windows Server 2012 R2. But something shocking happened when I did: Every VM that I moved to that new server performed so poorly that users could not stand to use the machine.
File transfers to or from the server were also taking an unacceptably long time to complete.
After some searching we figured out that the “Virtual Machine Queues” advanced driver option of the various network adapters in the server had defaulted to True.
Changing these settings to Disabled instantly restored performance of the server back to normal / acceptable levels and user complaints instantly went away.
Here are the step-by-step instructions to changing this setting on Windows Server 2012 R2 machine’s network adapters:
Open the Network Connections panel (right-click start, choose run… type: ncpa.cpl hit enter):
Right-click a network adapter and choose properties.
Click the Configure… button
Click Advanced, then scroll down to Virtual Machine Queues and change the value from Enabled to Disabled:
Here it is again on an Intel NIC:
Changing this setting for me at least made a dramatic improvement in network throughput and in Microsoft Hyper-V guest OS performance.
Darren Myher's Blog 
Extremely helpful!