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Something I've done recently has messed up my cpu usage in OS X (Snow Leopard). Looking at Activity Monitor, I see normal programs and normal cpu usage (15-20%) for all user processes. But the "% System" is constantly running between 40% and 50%.

Something is clearly wrong, but I can't figure out what is using all the CPU, since Activity Monitor or top seem to only show usage contributing to the "% User" statistic.

Any ideas on where to look?

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What system processes are using the CPU cycles? Can you post what daemons are running? – Steven Lu Dec 30 '09 at 18:52

Just for the record, it was the "cupsd" process. It was only using less than one percent itself in user space, strange considering I wasn't printing anything and had just reboot. Killing it instantly made the cpu go down to normal. After rebooting and logging in, the CPU went back up again. So I removed the printer (Canon MX850 in this case) in System Preferences, downloaded and installed the driver, and added it back. So far no problems.

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