XP - Processor usage monitor on Intel Speedstep chips

[russell2002]

Hi,

When I see the CPU usage as shown in task manager, is it usage against the full processor speed, or the current speed based on usage ?

Cheers.

 

[Nothinman]

Based on the current clock rate, but the CPU is always either executing or not and the percentags you see are just averages based upon a certain sample time so they're kind of misleading.

 

[russell2002]

If its on current clock speed its very misleading, because when it goes near 100% the processor speed increases and so the usage level is halved......

Therefor 95% cup usage is really 50% on my notebook......

And explains why my usage graph looks like a heart beat under heavy usage.

 

[Nothinman]

If its on current clock speed its very misleading, because when it goes near 100% the processor speed increases and so the usage level is halved......

Which makes sense considering how the numbers are generated. But one would imagine that the process using the CPU would quickly cause the usage to hit 100% at the new speed too unless it happened to finish right as the clock speed was adjusted. Or if the process is more I/O limited the CPU power won't help so it'll still be processing at the same speed so the usage would be 50% of where it was before the clock speed was adjusted.