cpucpu usageprocess
Assume the computer has a single core – what exactly does it mean for process A to be running at 100% CPU capacity vs (lets say) 10% CPU capacity.
If the CPU was 2.0 GHz, does that mean in a time slice for process A, that the processor was executing 2 billion steps per second (if at 100% cap), but would only be executing 200 million steps (if at 10% cap)?
What would cause the 100% scenario vs the 10% scenario?
If this process is causing high CPU usage, it's a driver. See these questions for further analysis support:
This process will use all remaining CPU resources that were not used by any other process. That's actually how CPU load is measured in the first place.
If the CPU spends 20% of it's time processing the Idle Process, then it's under 80% load. This process is nothing to worry about.
services.exe is the service control manager and shouldn't really be causing you any trouble.
What could cause trouble is svchost.exe which is the host process for Windows services. Every service in Windows is started through an instances of svchost.exe. So if a svchost.exe is causing high CPU load, it's a service running wild.
You can use Process Explorer to determine which services run inside a service host by simply hovering over the process:
This phenomenon is called processor Frequency Scaling, and it is done to address power-savings and thermal considerations. Scaling is performed by reducing the clock multiplier on the CPU, and thus reducing its overall frequency (GHz). Most processors operate at 100-166Mhz, but the clock rate allows it to perform multiple operations per cycle. My 3.8GHz CPU is actually a 100Mhz with a clock multiplier of x38. Scaling as you describe it is most common with Laptops, to balance performance with battery life and the systems limited ability to evacuate heat.
Frequency Scaling occurs below the OS, such that the OS will see the reduced capacity as 100%, so you will still see processes taking 100% CPU; its just 100% of the available CPU, not 100% of the total unscaled capacity.
Though Scaling occurs at the firmware level, Windows can automatically adjust the the Scale of the CPU based on its current needs, and accomplishes this via the Advanced Configuration and Power Interface (ACPI) to the BIOS/UEFI firmware. Windows will still throttle down the frequency when it can, but when the OS determines it is useful, it will raise the multiplier to whatever level it believes is appropriate. In your case you may want to reduce the minimum state while On-Battery, just to save some power and wear-n-tear on the CPU.
As for your side question, increasing the clock rate on a CPU is exactly what overclocking does, but of course there are limitations. your firmware needs to support the operations, and the hardware needs to be able to actually function with the altered specs, without burning out or producing an incompatibility with adjacent components (ram speed must be supported by ram, etc). I certainly would never OC hardware I cared about to 200%. I start getting Bluescreens and thermal problems when I add more than 6x to my default 34x system.
Best Answer
CPU usage is computed by the operating system's process/task scheduler. Indeed, if a CPU usage is 10%, that indicates that the task is actively running for 10% of the task scheduler's unit periods; other programs may run in the remaining 90% CPU time, or the OS will simply idle. Likewise, if the total CPU usage for all programs is 10%, that indicates that no programs on the system are being executed 90% of the time.
Since no programs run on the "bare metal" in a multitasked operating system (like Windows or Linux), CPU usage is a measure of what percentage your CPU's cycles are dedicated to running that one particular program. This is why if you have an infinite loop in a program, even though no "work" is being done, the CPU usage still approaches 100% (as the program is attempting to use every scheduling period offered to it by the operating system to execute some code).
Although processes are always running, they don't use 100% of the CPU in most cases since a process can wait for a particular event/interrupt to occur, or have indicated to the operating system to suspend/sleep its' operation for a short amount of time.