System Monitor remains busy for 15 - 20 minutes after startup

[Ashish Vijaywargiya]

Hello Friends,

I am using Ubuntu 8.04 since last few months. After startup it keeps
system monitor busy for about 15 - 20 minutes.
Please refer the image:
http://img641.imageshack.us/img641/9476/systemmonitorbusyinproc.png

How can I know which process is running in the background that is
busying this system monitor? And permanent fix of this problem.
This degrades the performance of my Laptop for initial 15- 20 minutes.

I am observing the same issue on two desktop machines.
Please help!

--
Ashish