The latest round of (thank the Lord, optional - at least for now) Microsoft updates includes a new version of Search.
Which comes with a new service.
Which pretty much halts the system for periods of anywhere from 5 to 25 seconds... at least on my test bed of systems at work, which are mostly Intel Pentium D 2.8 Ghz running Intel motherboards, where I've been having people who installed it turn it off when they call complaining that there machine is now "dog slow".
If you've installed the optional software with the August updates, and you are having similar problems, this is your probable culprit.
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