Make Activity Monitor show more than 4 cores worth of CPU usage in the Dock
There is a bug in Activity Monitor v10.8.0 (806).  If you select Dock Icon > Show CPU History, is automatically closes the floating window and appears in the dock.  If you attempt to switch back to the floating window, sometimes only one core appears.

Solution:
- Close floating windows
- Dock Icon > Show Memory Usage
- Quit and Restart Activity Monitor
- Dock Icon > Show Application Icon
- Quit and Restart Activity Monitor
- Monitors > Show CPU History

Now you should see all of your cores/vccores.  :-)

This bug is not always reproducible, but I've experienced it before.