On what appears to be every other boot of my computer, I find that three service host tasks consume a significant amount of CPU cycles.

If I let the computer sit, untouched, for 10-15 minutes, these three tasks remain the greatest consumers of cpu time. If I reboot, however, they stop being cpu hogs:

What surprises me is that I can reproduce this behavior by simply rebooting my computer, at which point the three service host tasks will resume their place as top CPU users.
I am looking for suggestions on how to troubleshoot this issue.