For what it is worth, I disabled the local backup - that was a pain because I lost much of the security I had in the backup. Time Machine and Spotlight seem for me to be the main (but not only) problems. The Time Machine backups appear to use more cpu than they should but that is a mute point. The bigest problem is after each backup Spotlight decides to "index" it. Yes, it now accesses the Time Machine disc and starts the labourious process of indexing.
The local backups took even more time and resource and again Spotlight had to index what it could. Removing the local backups made a big difference.
These backups and indexing takes place hourly by default. In my case the process is complete within 20 to 25 minutes but that is only 35 to 40 before the next one. This indicates a bit of a design problem but not the end of the world. The entensity of the processing is the major concern. When the hot (to the touch) computer with very noisy fans blowing like a hurricane interfers with you doing your work, something is very wrong. If I was planning to update all of my audio files and render a feature film I could understand. But when you are editing a simple text file it becomes a serious problem.
Apple, turn off indexing when running on batteries. In a trade off between finding a newly added file (where do they come from anyway) and being able to use your computer in a remote location -- using the computer in the remote location wins every time!
