Just to clarify, after bootup, if nothing is happening on the desktop (such as lunching apps, nothing really happening such as cloud sync, AV scan, etc.), and when in Balanced Power plan, normal behavior would be for a CPU to fluctuate between as low as 800 MHz, but, tinkering on the desktop reading forums, for instance, I routinely see clock speeds of 1200-2600 MHz.
Now if your CPU actually shows locked at some lesser speed, like absolutely fixed at 1.6 or 2.1 GHz, that is indeed a problem. (Make sure all BIOS settings are still correct, mostly defaults unless running MCE on a Z-series mainboard (unknown if this might apply given zero other system details given)
When sitting at desktop, launch HWMonitor....do you see clock speeds fluctuating from 800-4900 MHz as you open/close applications? (If you launch CPU-Z/bench/stress CPU, it should be locked at 4600 MHz for at least 90 seconds, then, if power limits/boost duration limits are not overridden, it might downclock to lower clock speeds to meet TDP goals, depending on mainboard/BIOS settings. Be sure to hit 'Stop' on CPU-Z afterward to avoid running stress test for beyond 10 minutes or so....; as long as clock speeds are not above 80C during, your temps are under control....