Tag Archives: slow network performance

Broadcom Network Adapters Causing Slow Network Performance

I wanted to give everyone a heads up on a major issue related to Broadcom NICs, these can be found primarily in top shelf HP/Dell servers that are used in production across the globe. The issue is related to poor network performance for virtual machines and this is due to a advance NIC setting which is referred to as “Virtual Machine Queue”.

VMQ is when network traffic is handled by the physical network adapter, it creates a queue of traffic which waits for everything to arrive and then routes it to where it should go. In my experience, this has killed file transfer speeds and what normally would take 30 seconds to complete will now take over 30min!

To disable this evil monster you can do it via Powershell like below:

another way of disabling this is locating your network card properties in Device Manager and going to the Advanced tab, the Virtual Machine Queue property will be in the list.

I originally faced this issue over a year ago and had posted a question over at ServerFault but seemed like no one had a clue on what might be the problem. Hopefully this saves someone the heads, cheers!