Just How Fast KVM Really Is?

To continue from my previous post on QEMU/KVM, I ran a bunch of additional tests and recorded the results. The aim was to provide a ballpark estimate for the performance of QEMU/KVM compared to native performance. I also took the time to test with VMware Player and Oracle Virtualbox. This isn't meant to be a scientific reference, but it can be used as a starting point for people interested in virtualization.

My computer system is now quite old: Intel Core i7 860, 12 Gb RAM and an AMD Radeon HD 5850 1Gb. My daily operating system is Debian GNU/Linux Sid x86_64. For testing, I also installed Windows 7 on a spare parition. Futuremark software (3d Mark) need valid licenses to be used for benchmark. Unigine Heaven is a free multiplatform benchmark. In order not to make the reading boring, I threw the details of the software I ran at the bottom of the article.


3d Mark 2006

Even though 3d Mark 2006 is now quite old, I find that it still represents DirectX 9.0c based games nicely. For VMware, I ran into some graphical glitches with textures and shadows. Click here to see a screenshot.

       Windows 7   QEMU/KVM   VMware Player   Oracle Virtualbox 
Score 17308 16130 11496 3824
SM2.0 6631 5948 4132 1878
SM3.0 8607 8013 5207 N/D
CPU 4563 4514 4233 2980

Average performance impact compared to baremetal Windows 7:

  • QEMU/KVM : -6.27%
  • VMware Player : -29.50%
  • Oracle Virtualbox : -61.43%1

3d Mark Vantage

3d Mark Vantage can not be run on VMware Player and Oracle Virtualbox because these virtualization software do not have DirectX 10 capabilities yet.

       Windows 7   QEMU/KVM   VMware Player   Oracle Virtualbox 
Score 15867 14623 N/D N/D
GPU 15813 14365 N/D N/D
CPU 16446 15457 N/D N/D

Average performance impact compared to baremetal Windows 7:

  • QEMU/KVM : -7.86%
  • VMware Player : N/D
  • Oracle Virtualbox : N/D

3d Mark 2011

With 3d Mark 2011, it's the same story. VMware Player and Oracle Virtualbox do not offer DirectX 11 capabilities.

       Windows 7   QEMU / KVM   VMware Player   Oracle Virtualbox 
Score 3980 3882 N/D N/D
GPU 3775 3739 N/D N/D
Physics 5761 5218 N/D N/D
Combined 3772 3545 N/D N/D

Average performance impact compared to baremetal Windows 7:

  • QEMU/KVM : -4.71%
  • VMware Player : N/D
  • Oracle Virtualbox : N/D

Unigine Heaven

Unigine Heaven was one of the first DirectX 11 benchmarks on Windows. It also runs on OS X and Linux if an OpenGL driver is providing the graphics. However for this test, I only ran the basic DirectX 9 benchmark. VMware Player produced some problems with the shadows effects, but it completed the benchmark. Click here to see a screenshot.

Virtualbox thew out the following error before closing: D3D9Render required number of buffers 4 is not supported.

       Windows 7   QEMU/KVM   VMware Player   Oracle Virtualbox 
Score 1897 1772 1234 N/D
FPS 75.3 70.4 49 N/D
FPS Min 9.4 8.9 8.5 N/D
FPS Max 150.1 132.3 113.7 N/D

Average performance impact compared to baremetal Windows 7:

  • QEMU/KVM : -7.57%
  • VMware Player: -25.93%
  • Oracle Virtualbox : N/D


To wrap things up, I must admit that I was quite surprised by the results. On one hand, I did not expect QEMU/KVM to be so close to native performance. With an average impact of -6.60% compared to native, it is now clear that virtualization can be used to run demanding software.

The other thing that surprised me was to see the results of VMware Player. Even with the visual artifacts that appeared during the runs of 3d Mark 2006 and Heaven, the frame rate was much higher than I expected. It is possible that the open source Mesa drivers for Radeon cards were affecting the 3D acceleration in VMware. For light gaming or for desktop acceleration of Gnome Shell and KDE4, VMware Player is an attractive proposition. It is also very easy to use.

Oracle Virtualbox was more in line with what I expected from desktop virtualization software. Even with the experimental 3D drivers, performances were low and there were a couple of graphical glitches with the normal Windows Aero compositing. However, Virtualbox still has the advantage of being included in most Linux distribution repository because of the GPL license.

It could be interesting to add a comparison with Xen and Hyper-V. Maybe in an other article.

Additional details


       Official websites 
3d Mark 2006 Link
3d Mark Vantage Link
3d Mark 2011 Link
Unigine Heaven Link

Other Software

         Official websites   Versions 
QEMU Link 2.0
KVM Link -
Libvirt Link 1.2.4
Linux Link 3.15
VMware Player Link 6.0.3
Oracle Virtualbox Link 4.3.12
Windows 7 Wikipedia Pro x64 SP1
Debian GNU/Linux Link Sid x64_64

  1. I did not count the SM3 test for the average score of Oracle Virtualbox.