XMir Performance Measured On Ubuntu 13.10
Canonical uses the Phoronix Test Suite in their Mir testing, so for this article I also used some tests they are likely not running, e.g. SuperTuxKart.
Some OpenGL Linux games take a larger hit than others.
The performance impact of Intel Haswell graphics with using XMir / Unity-System-Compositor on Ubuntu 13.10 is rather minor.