W3Wp.exe classic.NET AppPool CPU is high

I have server 2008 enterprise server run NS7.1.1.1, it has 16 GB of memory, and SQL 2005 server is running on the same box, sometime when I lunch the console it was extremely slow, I have to wait for long time to open any tab from the console menu.

I check the server task manager, on the processes, the  w3wp.exe for iis CPU is up and up, it show memory 1,129,724 K the number just keep going up,

I have IIS6 and asp.net 2.0 running.

Is any pathes for this?

Thanks

Lillian