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On Windows XP SP3, in Task Manager I assume that the "System Idle Process" is not counted as part of the overal "CPU Usage", therefore at any time the sum of both should be 100%, which seems to be true most of the time.

However sometimes, the CPU Usage may be at 50% or more while the idle process is still using 90% or more! For example when I start a program on my dual-core, I see one CPU going to 100% and the other staying fairly low, so the overall usage is around 60%, but the idle process is still above 90%.

What could be the reason for this discrepancy, and what is my CPU really doing at that time?

Note: I've checked the "Show processes from all users" box in the Processes tab.

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1 Answer 1

up vote 2 down vote accepted

XP Task manager is not a very good tool for looking at this kind of information, that is why MS added Resource Monitor to Vista and W7, a much better monitoring tool, task manager was also improved. XP does have Performance Monitor, type perfmon into a run box, still not anything like Vista-W7 tools

Some tools you can add to XP



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