QEMU

Install Ubuntu 20.04 LTS on QEMU for Windows

List available accelerators

qemu-system-x86_64 -accel help
Accelerators supported in QEMU binary:
hax
whpx
tcg

Performance comparison between accelerators

Read this topic "Meeting Minimum Hardware Requirements" first.

Tiny Code Generator

It sucks ...

# Single thread
qemu-system-x86_64 -cdrom ubuntu-20.04-desktop-amd64.iso -boot once=d -m 1G

# Multithread
qemu-system-x86_64 -accel tcg,thread=multi -cdrom ubuntu-20.04-desktop-amd64.iso -boot once=d -m 1G

Intel HAXM

Need to install Intel HAXM first, and disable Hyper-V.
If Docker Desktop was installed, this is not a good solution.

qemu-system-x86_64 -accel hax -cdrom ubuntu-20.04-desktop-amd64.iso -boot once=d -m 1G
Failed to open the HAX device!
Open HAX device failed
Failed to get Hax capability:6u
No accelerator found.

Windows Hypervisor Platform (recommended)

# with Windows Hypervisor Platform - good!
qemu-system-x86_64 -accel whpx -cdrom ubuntu-20.04-desktop-amd64.iso -boot once=d -m 1G
Windows Hypervisor Platform accelerator is operational