The Foldr server typically perfoms well when running on Microsoft Hyper-V. However, under certain circumstances / hardware configurations, worse performance than expected may be observed.
These issues may be the result of outdated host drivers, especially drivers for network adapters, or specific Microsoft technologies intended to improve performance not working as expected.
Some well documented issues that can impact Hyper-V virtual machine performance include:
1. Broadcom NetExtreme network adapters
2. Outdated NIC drivers are installed
3. Virtual Machine Queues (VMQs) are enabled on the host’s physical network adapters (any vendor)
&/or
4. Receive Segment Coalescing (RSC) is enabled on Server 2019 or higher on the Hyper-V vSwitches.
Virtual Machine Queues
VMQs are designed to offload virtual network processing to the physical adapter hardware and in turn improve virtual machine performance. When using certain branded network adapters and outdated drivers, VMQs are enabled by default by the driver (this is the case for Broadcom NetExtreme) and without other manual changes to the host system, can dramatically degrade performance.
Note that other manufacturers such as Intel, do not automatically enable VMQs by default.
Always ensure your server is running the latest drivers available from the network vendor. In the case of Broadcom, the latest available drivers should resolve the issue, however our recommendation is to disable the use of VMQs where possible on the physical network adapters in the Hyper-V host. You can disable VMQs in the properties of the physical adapters in Control Panel within its Properties >> Configure >> Advanced tab. If you wish to use VMQs in the host, ensure they are only enabled if the NIC hardware is capable of properly supporting it.
Disabling RSC and VMQs:
https://woshub.com/poor-network-performance-hyper-windows-server/
https://community.spiceworks.com/how_to/124202-how-to-disable-vmq-with-powershell
Additional information:
https://www.theictguy.co.uk/server-2019-hyper-v-slow-network-file-transfer/
https://community.progress.com/s/article/Networked-connections-slower-on-Hyper-V