What is "Processor Clock Tester" clock rate?

Specs on some GPUs list “Processor Clock Tester (MHz)” where “Processor Clock (MHz)” is usually listed. For example, for GT 630 (Kepler) we have

Graphics Clock (MHz): 902
Processor Clock Tester (MHz): 1804
src: http://www.geforce.com/hardware/desktop-gpus/geforce-gt-630/specifications

What does this “Tester” suffix mean? Is it any different than simply “Processor Clock”?

Also, shouldn’t Processor Clock for GT 630 Kepler be same as Graphics Clock - as always on Kepler?