By default, your cpu and graphics will run on lower performance when on battery.
You need to run plugged in for max cpu and graphics performance.
The default base clock of your processor is 1.6.
It will turbo up to 3.4 when conditions are right.
Turbo applies to just one core and will only do that when thermal conditions permit.
Thermals are an issue with laptops where size and weight constraints prevent truly good cooling.
Keep your cooling airways clear.