What Is a Virtual Machine?

A virtual machine is a software-defined computer that runs inside a real one. It boots its own operating system, gets its own disk, its own memory, and its own network connection, and it thinks it is a physical machine — even though every part of it is a file on the host.

This guide explains what a VM is, how it works, what a hypervisor does, and when running one on your Mac is the right call.

The short version

A piece of system software called a hypervisor sits between your real hardware and the guest. The hypervisor carves the host's CPU, memory, disk, and network into virtual versions, and an operating system installs and runs on top of that virtual hardware exactly as it would on a physical machine. The guest operating system cannot tell the difference, and neither can the applications running inside it.

That is the whole idea. Everything below is detail on what each of those words actually means in practice.

How a virtual machine actually works

When you start a virtual machine, the hypervisor hands it a slice of the real hardware:

• A virtual CPU count that maps onto the physical cores.
• A slice of RAM reserved for the guest while it runs.
• A virtual disk file on the host's filesystem, presented to the guest as a block device.
• A virtual network interface that the guest treats like a real NIC.

To the guest operating system, those resources look exactly like physical hardware. It installs and boots without knowing that the disk is a file or that the RAM is shared. The hypervisor takes care of pretending the resources are real: scheduling the guest's virtual CPUs onto the physical cores, translating memory addresses, emulating a disk controller, and presenting a network interface.

This is why the CPU architecture matters. If the host and guest share an instruction set, the guest's code runs natively on the physical cores. If they do not, every instruction has to be translated, and that translation is what an emulator does. A virtual machine in the strict sense runs natively; an emulator translates.

What a hypervisor is

A hypervisor is the software that creates and runs virtual machines. There are two kinds:

• Type 1 hypervisor — runs directly on the hardware. This is the model used in data centers (VMware ESXi, Microsoft Hyper-V Server, Xen).
• Type 2 hypervisor — runs as an application on top of a host operating system. This is the model used on a Mac or PC.

On Apple Silicon Macs, Apple's own Virtualization framework is a Type 2 hypervisor built into macOS itself. Kyvenza uses it for macOS and ARM Linux guests, and a separate QEMU-based engine on the Hypervisor framework for Windows 11 on ARM. Both engines are Type 2: they sit on top of macOS, they do not replace it.

VM versus physical machine

A physical machine is hardware you can touch: a CPU package, RAM modules, a disk, a network port. A virtual machine is a set of files on the host's disk plus a runtime process that pretends to be hardware.

Performance is close to native when the host CPU and the guest CPU share an instruction set. That is the case for Apple Silicon running ARM guests — the same arm64 instructions that run on macOS also run inside the VM, so the only overhead is the hypervisor's own bookkeeping. The resources are still shared, though: a heavy VM will slow down other work on the host while it runs, and disk I/O can become a bottleneck if the host and guest are reading from the same drive.

When the architectures do not match, the comparison is much worse. An emulated x86 guest on an Apple Silicon Mac runs every instruction through a translation layer, which is why emulated x86 on ARM is slow even on fast hardware.

VM versus container

Containers isolate applications; VMs isolate whole operating systems.

A virtual machine runs a full guest operating system with its own kernel. A container shares the host operating system's kernel and isolates only the application layer above it. Containers start faster, use less memory, and are easier to scale horizontally. The catch is that a Linux container on a Mac is still running a Linux kernel — usually inside a hidden VM, since macOS does not have a Linux kernel to share.

Pick a VM when you need a real, separate operating system (Windows, a different Linux distribution, a second macOS). Pick a container when you only need isolated applications on the same operating system as the host.

What a VM is on a Mac

On Apple Silicon Macs, a virtual machine is a guest operating system — typically Windows 11 on ARM, macOS, or an ARM Linux distribution — running in a window on the macOS desktop. macOS ships with Apple's own Virtualization framework, so a VM is a first-class citizen on the platform rather than a third-party hack.

Kyvenza is a Mac app on top of that framework. It handles the disk, memory, CPU, and network configuration for you, ships the network and display drivers for Windows guests, and keeps the lifecycle (snapshot, clone, pause, delete) in one place. You pick the guest, point the wizard at an installer image, and the VM appears as a window on your Mac.

x86 guests are not supported on Apple Silicon through Kyvenza. The reason is structural: Apple Silicon runs ARM natively, and emulating x86 is exactly the kind of translation that defeats the point of running on Apple Silicon in the first place. If you need an x86 guest, look at UTM or another tool with an emulation path.

Frequently asked questions

What is a virtual machine?

A virtual machine is a software-defined computer that runs inside a real one. A program called a hypervisor carves the host's CPU, memory, disk, and network into virtual versions, and an operating system installs and runs inside that virtual hardware exactly as it would on a physical machine. The guest operating system cannot tell the difference, and neither can the applications running inside it.

What is a virtual machine used for?

The three most common reasons are (1) running an operating system that is not the host's — for example, Windows 11 on a Mac, (2) testing software in a clean, disposable environment that can be rolled back, and (3) isolating untrusted code or third-party tools from the machine you actually work on. Inside a business, VMs also power servers, developer environments, and CI runners.

How does a virtual machine work?

A hypervisor mediates between the real hardware and the guest. It schedules the guest's virtual CPUs onto the physical cores, translates memory addresses, emulates a disk controller, and presents a virtual network interface. The guest operating system runs unmodified on top of that virtual hardware; the hypervisor takes care of pretending the resources are real.

What is a virtual machine on a Mac?

On Apple Silicon Macs, a virtual machine is a guest operating system — typically Windows 11 on ARM, macOS, or an ARM Linux distribution — running in a window on the macOS desktop. macOS ships with Apple's own Virtualization framework, so a VM is a first-class citizen on the platform rather than a third-party hack. Kyvenza is a Mac app on top of that framework that handles the disk, memory, and network configuration for you.

What is the difference between a virtual machine and a physical machine?

A physical machine is hardware you can touch: a CPU package, RAM modules, a disk, a network port. A virtual machine is a set of files on the host's disk plus a runtime process that pretends to be hardware. Performance is close to native when the host CPU and the guest CPU share an instruction set (the case for Apple Silicon running ARM guests), but the resources are still shared, so a heavy VM will slow down other work on the host while it runs.

What is a hypervisor?

A hypervisor is the software that creates and runs virtual machines. There are two kinds: a Type 1 hypervisor runs directly on the hardware (the model used in data centers), and a Type 2 hypervisor runs as an application on top of a host operating system (the model used on a Mac or PC). On Apple Silicon Macs, Apple's Virtualization framework is a Type 2 hypervisor; the QEMU engine Kyvenza uses for Windows 11 on ARM is a Type 2 hypervisor as well.

What is a virtual machine vs a container?

A virtual machine runs a full operating system with its own kernel, while a container shares the host operating system's kernel and isolates only the application layer above it. Containers start faster and use less memory, but they cannot run a different operating system — a Linux container on a Mac still runs a Linux kernel inside a hidden VM. VMs are the right tool when you need a real, separate operating system; containers are the right tool when you only need isolated applications.

What is a virtual machine on Apple Silicon?

On Apple Silicon Macs, a VM runs an ARM guest operating system on the M-series chip using Apple's native Virtualization framework, so there is no instruction translation and performance is close to bare metal. ARM Linux distributions and macOS ARM guests run on that native path; Windows 11 on ARM runs on a separate QEMU-based engine with TPM 2.0 and Secure Boot enabled by default. x86 guests are not supported, because emulating a different CPU architecture would defeat the point of running on Apple Silicon.

Can a virtual machine slow down your computer?

Yes, because a VM takes real CPU cores and real memory away from the host operating system while it runs. A heavy VM will reduce the resources available to the apps on your host, and disk I/O can become a bottleneck if the host and the guest are reading from the same drive. The CPU architecture matters: an ARM guest on Apple Silicon runs at near-native speed, while an emulated x86 guest on the same hardware runs much slower because every instruction has to be translated.

Is a virtual machine the same as an emulator?

No. A virtual machine runs guest code on the same CPU architecture as the host, so instructions execute natively. An emulator translates instructions from one CPU architecture to another, which is what makes it possible to run, for example, x86 software on ARM hardware — but at a significant performance cost. Apple Silicon VMs run ARM guests natively and do not emulate anything, which is why x86 guests are not supported.

How is a virtual machine different from dual boot?

Dual boot runs one operating system at a time and requires restarting the computer to switch. A virtual machine runs the guest operating system in a window alongside the host, with no reboot and no disk partitioning. You can have macOS open on the screen and a Linux VM running in a window on the same desktop, copy text between them, and shut the VM down without affecting the host.

What is the best virtual machine for Mac?

It depends on the guest. For Windows games, 3D applications, or anything GPU-heavy, Parallels Desktop is the stronger product and the one Microsoft lists as authorized. For x86 emulation or experimental setups, UTM is the usual choice. For macOS and ARM Linux guests plus everyday Windows 11 on ARM tools, Kyvenza runs on Apple's own framework with pre-filled defaults and a one-time price. Pick by the guest you need to run first, then by the app.

Next steps

• How to make a virtual machine — the practical walkthrough.
• Parallels vs UTM vs VMware Fusion vs Kyvenza — picking the right tool.
• Kyvenza on kyvenza.com — download, pricing, and the supported guest list.