Ubuntu 11.10: Xen vs. KVM vs. VirtualBox
Written by Michael Larabel in Software on 31 October 2011. Page 4 of 7. 27 Comments

Running OpenSSL produced results quite similar to John The Ripper.

Running 7-Zip in a KVM instance takes about a 10% performance penalty while VirtualBox dropped by about 15% and Xen was at nearly 30%.