When you have enough product (you certainly do) , it's usually good idea to turn off "Update on Save" option and use manual indexing. For example I usually use cron to run indexing scrip every night. You can find command line indexing script from shell folder.
Easiest way to run it is php -f shell/indexer.php reindexall (this will reindex everything, if you want to be more specific you can play around with options this script has).
Tanel Raja
