My PC is too slow these days (after some "updates" from Administrator). When I look in to the Resource Monitor, I see when the PC is slow, in Tab CPU, I have 1 Blue Line stick to 100% threshold, what is it mean, and is it correlate with my PC's cause?
See also How to understand disk activity view charts of the Windows 7 resource monitor?– VadzimJan 30, 2019 at 12:08
It's the maximum total of your PC processor(s) at normal clock speed. This shouldn't be any cause to your degraded performance issues either. It's normal to read some value in percentage based on how your CPU is clocked speed wise in BIOS, etc.
Maximum Frequency in Resource Monitor is the same as the Processor Performance% of Maximum Frequency counter in Performance Monitor. For example if you have a 2.5 ghz processor which is running at 800 mhz then % of Maximum Frequency = 800/2500 = 31%. So the processor is running at 31%, or 800 mhz, of the processor's maximum frequency of 2500 mhz (2.5 ghz).
The "best" percentage of maximum frequency is subjective. Basically, you want the CPU running at a frequency that is fast enough to do what you want while using the least amount of power so it doesn't drain your battery or increase your electric bill unnecessarily. Your power plan in Windows is part of what determines the frequency as well as settings in the computer's BIOS.