====== VirtualBox Windows 10 / 11 performance issues ======
===== Intro =====
It's possible to have severe performance issues using VirtualBox on Windows. This is usually caused by Microsoft forcing their own Hyper-v hypervisor to startup with Windows in the background. This blocks direct access to intel's and AMD's virtualization on the CPU's. VirtualBox is therefore forced to fallback to Hyper-V, running all VM's as nested VM's on top of it. \\ \\ This issue is indicated with a green turtle icon in the bottom taskbar of a started VirtualBox VM (as seen in the example image). \\ {{:public:windows:virtualbox-performance-issue-greenturtle.png?400|}}

===== Solution 1: =====

I would highly recommend using a Linux OS for virtualization when possible! One of my preferences is Proxmox, which is free to use and supports a wide range of advanced features.
===== Solution 2: =====
==== 1) Disable the Microsoft Hypervisor: ====

<code bash Type: >
bcdedit /set hypervisorlaunchtype off
</code>

==== 2) Disable Device guard: ====
On some Windows hosts with an EFI BIOS, DeviceGuard or CredentialGuard may be active by default, and interferes with OS level virtualization apps in the same way that Hyper-v does. These features also need to be disabled. 

On Pro versions of Windows you can do this using **gpedit.msc** 

<code bash Type: >
set Local Computer Policy > Computer Configuration > Administrative Templates > System > Device Guard > 
Turn on Virtualization Based Security to Disabled.
</code>

{{ :public:windows:virtualbox-performance-issue-disablevirtualizationbasedsecurity.png?400|}} 

CredentialGuard is a subset of DeviceGuard, so disabling the former should be enough. If you cannot use gpedit for some reason then the equivalent registry hack is to find the key 
<code bash Type: >
HKLM|SYSTEM|CurrentControlSet|Control|DeviceGuard|EnableVirtualizationBasedSecurity|Enabled and set it to 0.
</code>

==== 3) Disable core isolation: ====
Core isolation [includes] security features available on your device that use virtualization-based security. This is why they can interfere with VirtualBox and other virtualization tools. Disable them as follow: 

<code bash Type: >
On Win10 hosts, check Settings -> Device Security > Core Isolation Details and make sure all settings in this panel are turned off.</code>

{{ :public:windows:virtualbox-performance-issue-disablecoreisolation.png?400|}}

==== 4) Windows rituals: ====
Reboot your system for the new configuration to take affect! :-)