Exchange cpu utiliztion is 100%

Hi,

While using outlook sometimes i am facing slowness issue i.e. when ever i clicked on any mail it will take time to open that mail, mean while on system try i will get the message outlook is trying to receive the messages from mail server.

At that time we observed that exchange cpu utilization is 100% and the process that are taking entire memory is Store.exe, services.exe, wmiprvse.exe, wmgmta.exe, w3wp.exe

What are the above services and why these are all taking huge amount of memory?

Thanks,
knagaraj