When the thermal sensor is tripped on my laptop everything acts like it's running on a 286. Processes which normally finish in 2 seconds are eating up 100% CPU and taking 10-20 seconds.

My server periodically was acting the same way. Finally found the culprit. I had my routers send there logs to syslogd. My wife and I both had torrents active, and the deny policy on the router/firewall was sending about 20-30 entries a second. Needless to say my messages log was about 600M daily.

After turning the sending of the logs, my server is now acting normally.

Just wanted to mention this here in case anyone has similar symptoms.

If there's 20 to 30 messages flowing back AFAIK they have to be unique (or alternating) to be logged individually because else syslog would just say "last message repeated n times", so wrt perf, I wonder if there's not more than just the firewall policy coinciding? I mean, if a thermal is triggered, doesn't this also affect CPU throttling down?