If you ask Intel, they will tell you that anything less than Tjmax (~100c) is acceptable. What garbage!
I believe that a Tcontrol threshold should be established for these processors and cooling (fan speed control) solutions should adhere to the standard guidance for the Tcontrol threshold.
Here is a more-reasonable set of values:
Ideal: 30's (or less)
Fully loaded Temperatures:
Ideal: 70's (or less)
Hope this helps,