My System Properties window has the below text (also see screenshot). What does the "1.20 GHz " refer to?
HP Compaq dc7700p Convertible
Intel(R) Core(TM)2 Duo CPU
E4400 @ 2.00GHz
1.20 GHz 3.50 GB of RAM
Physical Address Extension
Most modern Intel CPUs have SpeedStep, which means that the CPU will reduce its speed by lowering the multiplier and lower its voltage to conserve power when it is idle. Your CPU is currently running at 1.2GHz, but has a maximum frequency of 2.0GHz when under load.
The second speed usually refers to the actual speed of the processor, while the first is the "Rated" speed that the processor is designed to run at. You see this most commonly if the processor is clocked down to save power when idle. It is being word-wrapped to the second line because of the width of the window.