Server 2012R2 Broadcom 1Gb NIC transfer speeds dropping to below 20Mb/sec

Hi Experts,

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.
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Tony GiangrecoCommented:
I've had the same problem in a teamed setup using a Dell 2950. After breaking the team and disabling the 2nd network adapter, it worked much better.

Hope it helps!
Philip ElderTechnical Architect - HA/Compute/StorageCommented:
Broadcom Gigabit NICs have VMQ (Virtual Machine Queues) turned on by default for all ports.

Here's why that setting needs to be disabled: Broadcom Gigabit and VMQ.

Please disable VMQ on _all_ Gigabit ports and reboot.

Things will settle down after that.
murphygeAuthor Commented:
Apologies for the delay in getting back to this question. The problem turned out to be a disk issue, despite my opening comments - after disk replacement, file transfer performance returned to normal.

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murphygeAuthor Commented:
Solution was a separate issue not part of the question.
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