Eli5: How is it that my CPU is operating at a 3 GHz speed but utilization is 50%, and sometimes the speed is 1.8 GHz but utilization is 100%?

Question

I mean, what’s the difference between both? Why do I never see 100% utilization at 3 GHz even when using the most resource intense tasks?

In: Technology

Answer 1

There can be many reasons why your CPU is almost never at its highest clockspeed when fully utilized

It might be power constrained, meaning that when running all of its cores, it cannot draw enough power to keep going faster

It might be thermally throttling, meaning that it runs too hot to draw more power and run faster

There can also be architectural constraints why these things happen, like signal integrity, which can be correlated to power draw and thermals. Suffice it to say, that every CPU on the market has higher clockspeeds when using just one core compared to using all of them at capacity