Speed boost with private handlers?

[Wilhelm Sanke]

The "What's new" text and the "Engine Change Log" for 2.8.1 state for 
"private handlers" that there is a "speed boost as private handlers do 
not have to go through the message path".

Has anybody experienced such a "speed boost" and could he/she provide a 
sample script or sample stack where such a speed boost is apparent and 
can be measured in comparison with a non-private handler?
 
Regards,

Wilhelm Sanke
<http://www.sanke.org/MetaMedia>