Ubuntu 11.10: Xen vs. KVM vs. VirtualBox

When turning the focus to cryptography from ray-tracing, KVM continued to be the fastest virtualization contender at 97% the raw speed of the system. Closely behind with the DES workload was VirtualBox and the Xen DomU instance was at just 69% the speed of bare metal.

Ditto.

When running the Blowfish test, VirtualBox and KVM were both fast, while the DomU guest continued in its ~30% performance penalty.