Hyper-V Causes Extreme Degradation of Performance on WiFi

I have a machine that is in a temporary location. The location makes it necessary to also temporarily connect using WiFi. As a result, I have a USB based WiFi 5 adapter connected to this machine. I'm moving large amounts of data to the machine but I'm getting an amazingly great 100MB+ per second over the WiFi connection.

I enabled Hyper-V on this system and my WiFi performance plummeted to around 30 to 35MB / sec. Just to make sure that is was really Hyper-V that was responsible for this, I uninstalled Hyper-V and my performance is back up to 100MB+ / sec.

Anyone know if such drastic drops in performance are expected or if there is any sort of "tuning" that can be done to alter this behavior?

System Details:

MSI X570-A Pro Motherboard
AMD Ryzen 3900X CPU
32B RAM
Samsung 970 EVO NVMe 500GB SSD (Windows / Application Installation Disk)
Western Digital WD100EMAZ 10TB HD (This is where all the data I am copying is being stored)
WiFi Adapter: USB 3 Netgear Nighthawk A7000 (AC1900 WiFi 5 adapter)
WiFi Router - ASUS RT-AX92U Router (WiFi 6)

EDIT: Forgot one important detail: This system is running Win 10 Pro 20H2

hsehestedt said:

I enabled Hyper-V on this system and my WiFi performance plummeted to around 30 to 35MB / sec. Just to make sure that is was really Hyper-V that was responsible for this, I uninstalled Hyper-V and my performance is back up to 100MB+ / sec.

...This system is running Win 10 Pro 20H2

One of my Hyper-V machines has 20H2. I use WiFi for all my machines, and can't say I've noticed the Hyper-V machines being significantly slower than those without.

So I tested the speed on the 20H2 machine with and without Hyper-V installed. For the test I copied the same file from my network storage each time. Yes, with Hyper-V it was a little slower, but not dramatically so - 130Mbps vs 150Mbps.


Hyper-V installed




Hyper-V unistalled

I notice a large drop in network performance if I have an external switch set up in Hyper-V. I don't notice any performance decrease with an internal switch set up.

Internal Switch:


External Switch:


This test is done from the host.

Bree and NavyLCDR, thank you both for actually making the effort to do the testing that you both performed.

Very interesting because that was actually exactly what I was doing - connecting my VM to an external switch set up in Hyper-V. I should have provided that as a data point but neglected to do so.

I guess that as my next test I may have to try VMware to see if I get similar results.

Unfortunately, the performance hit would kill me because I'll be shuffling around upwards of 1TB per day for the next couple of weeks and the performance hit makes the difference between a 3 hour transfer and 8+ hours.

When all is working well I'm getting 100+ MB per second or roughly 930Mbit / sec. Pretty amazing for a WiFi 5 adapter. Can't wait to try WiFi 6 on that machine when when I also add more SSD storage space

This is a long standing issue

networking - Hyper-V External network switch kills my host's network performance - Super User

Thanks for that info. I may have to try some kind of experimentation like setting up a seperate network adapter devoted to only Hyper-V.

I've never really done too much with Hyper-V because I've favored VMware workstation, but with the removal of major features in the latest version I'm starting to use Hyper-V more.