Wow,,, isn't the max on that CPU 100 °C? I wouldn't want to try running one of my machines that close to max for any length of time, max minus 30 is what I personally shoot for

(100°C = 212 °F = boiling point of water at standard pressure)
For others who might not be as lucky or plan to keep their machine a very long time:
The hotter a processor is, the more Electron Transmigration occurs. That degrades semi-conductors. Better cooling lessens this degradation. Cooler components should result in longer product life. Not every processor is the same and may not cope with heat stress the same way. Intel's 0 to 100 °C is what they will warranty for.
Anyhoo, for the original question it would really matter WHICH exact CPU is in the machine...
T420 & X220:
Core i3-2310M = 35W
Core i5-2410M = 35W
Core i5-2520M = 35W
Core i5-2540M = 35W
Core i7-2620M = 35W
T520 (plus the above cpu's):
Core i7-2720QM = 45W
Core i7-2820QM = 45W
then the W and L series + ???
Which core duo is in your machine? (There are several diff 1.8GHz) Looks like Merom 17W or 35W, or Yonah at 31W.
For anyone answering this thread, please include what CPU & ambient temperature(room temp), would be interesting to see from a "how well it's designed" point of view.