XP Pro SP3 start-up slow

At start-up, Windows Task Manager shows high initial cpu activity which quickly settles down to 0%. After a delay of about a minute, activity starts again, the cpu is busy for another minute and then settles down to 0%.

During all this time (more than two minutes), the mouse cursor, if moved from the screen area and placed on the task bar, changes from the arrow head to the hour glass.

I hadn't noticed this behaviour until recently

Why does the cpu become inactive and then wake up again?

 

As startup items are launched, the CPU activity will increase. The same occurs if your AV auto updates on reboot or coming out of Stand By/Sleep or if it scans. It may "wait" for other tasks to finish before doing so.

 

Thank you mdonah, but that doesn't explain to me why, after cpu activity settlles to zero and remaining at zero for a minute, it starts up again.

 

Sure it does. Some services and processes are delayed at startup.

You probably installed something that loads at startup, but is a delayed start.