The names of the executables on your system might be different and they might actually be symlinks to one another, so you should definitely check it out before using it. This is quite faster, but our processor must support it for Qemu to be able to use it.

By using KVM, the Qemu won’t emulate the hardware, but use the hardware we already have and build upon that. Qemu-kvm: this is a Qemu binary that takes advantage of using the underlying hardware virtualization features supported by our process and is the main reason we’ll be using it.By using emulation, Qemu will completely emulate the hardware as well as the software and won’t use the actual hardware we have, which results in slower performance. Qemu-system-x86_64: this is a Qemu binary that emulates the virtual machines without using the underlying hardware virtualization features supported by our processor.After installation, where will be a number of Qemu-* binaries available on our computer, but we’re mostly interested in the following: Instead we’ll start with an article supposing that we already installed them.

We won’t go into installing the Qemu and KVM, because there are really a lot of resources out there that show us how to do that. In order to do that our computer must support the virtualization technology, which we can check by executing “cat /proc/cpuinfo” and checking whether the cpuflags list vmx or svm flags in which case the virtualization is supported by our processor. In this example we’ll be using underlying KVM. We almost always want to choose to use Qemu with KVM/XEN, which will be quite faster than using it alone.

Standalone: if Qemu is used in standalone mode without also using KVM/XEN, then it’s running entirely in user-space, which results in slower performance.

Together with KVM/XEN: Qemu is used together with Type-I hypervisor like KVM or XEN, which results in faster performance.

Virtualbox vs qemu performance