Whenever I turn on my laptop, the CPU has around 3.00 GHz (base speed 2.90), but if I let the laptop go on for longer, the speed goes down to 0.38 (according to task manager) and it keeps everything very strong,
The CPU temperature is always 30 degrees high, according to Core Temp
It is normal that the CPU clock lowers when the CPU has nothing or very little to do. This saves power and the CPU does not get so warm.
However, if it does not go up even under load, then look under "Power Options" to see if it is in energy-saving mode or something.
Sounds like there's something on the software side.
Energy saving mode or such fun turned on?
By the way, processors in laptops generally run slower and slower while idle, but in the long term programs also cause the CPU to be more heavily used elsewhere by default.)
If the performance is not required, then the processor clocks down - this saves power. At system startup, a few programs and processes have to be started first, it just needs performance. Only the Task Manager and Desktop pull almost nothing.