I referred to these two processes tangentially in Microsoft laptop gripes, but based on referrer hits and email they deserve a post of their own.
Systems Management Server pushes out patches and keeps your software updated via an agent that's installed on your PC. This agent shows up in task manager as CcmExec.exe (where ccm stands for change and configuration management), and in the services list as the SMS Agent Host. Normally ccmexec doesn't do much, but (depending on your setup) it may periodically kick off an Office update process called inventory.exe. Doing an inventory involves a lot of disk seeking, and unfortunately SMS isn't smart enough to notice if you're actually using a laptop on battery power.
This can lead to the poor user experience of "I was sitting in a meeting minding my own business, and all of a sudden something called inventory.exe started thrashing my laptop's disk, and I couldn't get anything done for two minutes". To avoid this, you can stop ccmexec when you want a quiet laptop, and then restart it when you want to be a good corporate citizen again. Needless to say, this is undocumented, unsupported, and liable to leave you with an unpatched machine and an angry sysadmin if you forget to restart the service - but if you got this far you probably realize that anyway. So here are three alternative methods:
Ideally, I'd like to stop and start ccmexec programatically as I go on and off battery power. My Toshiba Tablet PC has an extended set of power schemes that almost does what I want, but not quite - it can changes power schemes when I run an arbitrary program, but not run an arbitrary program when I change power schemes.
Update: clarified where inventory.exe comes from, thanks to SMSPerfGuy's comment.
Update #2: the latest version of the Office Update Inventory Tool significantly reduces the CPU consumption while performing an inventory - so don't stop the SMS service if you're still seeing problems, ask your admin to upgrade the inventory tool instead!