What is syslogd?

It's part of the Apple System Logging infrastructure. You can find information about it by typing "man syslogd" from a terminal window. Also "man asl" and "man syslog" might give some additional info. Basically, it is a daemon that processes log messages sent to it by a variety of other running processes. These log messages, once processed, are put in a variety of log files.

It could be that some process is engaged in some pretty heavy logging, causing that syslogd to eat CPU. You could take a look in /var/log to see if any file in there growing rapidly.

Also check the /etc/syslog.conf file which is the configuration file for syslodg. You can check the syslog.conf man page (*man syslog.conf*) for more information.
A useful command for watching a file's output (/var/log/system.log in this case) is: tail -f /var/log/system.log

Mihalis.

Why would you expect killing Firefox to make any difference?

Unless Firefox is the app that's generating all the logs, it wouldn't be relevant.

What you need to do is look at the logs that syslogd is writing and see what it's trying to tell you about.

You can look in /var/log to see the various log files that syslogd writes. Chances are if it's that busy then the log file in question is going to be pretty big, so you can use the file size as a hint as to which file to look in. You can also look at modification dates since the log will be modified real-time.

Once you identify the log file, tail the log file to see the most recent entries. Hopefully something there will provide a clue. If not, post it here for review.

If you prefer, you can use the Console application (in /Applications/Utilities) to examine the log files.

- cfr