What is a CPU?
The central processing unit executes program instructions, performs calculations and coordinates the order in which system tasks run. Everyday apps, games, compression tools and creative software can place very different demands on it.
What do cores and clock speed mean?
Multiple cores can handle more streams of work at once. GHz is one indicator of operating speed, but architecture, power limits, cooling and software design also affect real performance. Comparing GHz alone can therefore be misleading.
How can you check it in Windows?
Open Settings > System > About to identify the processor. Task Manager > Performance > CPU shows current load, speed and core information. High usage is not automatically a fault; identify the app creating the load and whether the behaviour persists.