Awkward Linux Power Management With Xen
Where the results turn around is when all of the CPU cores are maxed out. With the Xen support enabled, the power consumption was down by nine Watts! Switching to the Xen kernel for this multi-threaded ray-tracing benchmark dropped the power consumption by 20% compared to the Ubuntu 11.10 stock kernel.
However, the Ubuntu 11.10 stock kernel was noticeably faster than when the kernel was booted with Xen virtualization support.