Less than two years ago, I bought a Lenovo Thinkpad R500.

When using the CPU heavily, it sometimes decides to reboot.

I am using Linux, and a widget shows me the CPU temperature. The PC usually reboots when the temperature of the first core gets over 100°C

Since I switched from Ubuntu 2010.10 32bit to Ubuntu 2011.04 64bit, it crashes much more often.

I survive using these techniques:

1. When in the office, I use a laptopcooler.
2. When outside, I underclock to 800 MHz, by doing so it does not get too warm.

QUESTION:

Is it normal that a Thinkpad crashes if the CPU is at 100% for more than 10 minutes?

How can I use the full power of my computer, for instance when showing CPU-hungry business intelligence tools to clients?

The computer does not really feel that hot. Maybe the sensor itself is reporting wrong temperatures? Can I tell the BIOS to ignore it?