Last week I tested the new -controversial- Qemu accelerator kernel module.
These are the results of the nbench2 benchmark:
Using the accelerator kernel module:
floating point: 9.813
Running the test on my machine without any emulator involved:
floating point: 11.083
Quiet impressive imho... of course -just as with VMware- as these "emulators" actually just execute the assembly code, they should approach native performance. It's a whole different story when IO-bound applications are benchmarked.