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Comment by dboreham | Hacker News Reader

> moves my main Windows into now a parent VM over the Type 1 hypervisor

Are you sure about this? It seems unlikely that NT would change significantly depending on whether or not it is hosting a WSL2 guest. I've never noticed anything different about my Windows since using WSL2.

> Windows filesystem from WSL2 and vice versa

/mnt/C/

\\wsl.localhost\Ubuntu

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WSL2 is architecturally designed to run under Hyper-V, so when you activate WSL2 on your machine, Hyper-V runs on bare metal and your Windows installation just becomes another VM running inside it next to the WSL2 Linux environment. Unfortunately this is imho not explained as well as it should be, because, while most of the time most people won't notice any difference, there is a measurable impact with regards to performance (in games, for example). It depends on your specific setup how bad it gets, and in most cases it's more of a theoretical performance hit than a noticeable one, but it is still there.

It downclocks my ram to 800mhz if I enable vt in bios. My new cutting edge system turns into a pentium 4. Apparently this is a bug with windows 11. Hope it gets fixed

As I said, it is NOT documented well; and even when you do confirm that WSL2 engaged Hyper-V, the ramifications are even more poorly explained.

But yes, everything I've read and experienced indicates that:

1. WSL2 IS a VM and it necessitates installation of certain portions of Hyper-V, which as Type-1 hypervisor, means your primary windows partition is no longer bare-metal but rather now a parent virtual machine.

2. This has impact on running other Type 2 hypervisors such as VirtualBox or VMWare etc; as well as some types of performance-intensive applications and games.

https://docs.microsoft.com/en-us/windows/wsl/faq

It is true for any system that has Hyper-V enabled and should work perfectly fine. Same as if you have a Windows VM guest or a traditional Linux VM. WSL2 uses and manages a small VM under the hood so enabling it will cause this change to the windows boot process if it was not already so.

Yeah it actually does. Crazy, I know.

They’re also doing the same for Windows 11 by default now too I believe.

> In addition, if you have Hyper-V enabled, those latency-sensitive, high-precision applications may also have issues running in the host. This is because with virtualization enabled, the host OS also runs on top of the Hyper-V virtualization layer, just as guest operating systems do.

https://docs.microsoft.com/en-us/virtualization/hyper-v-on-w...

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