Point of reference:

astounded to find that both cores of the processor were running at well over 85 degrees centigrade.

85C was a commonly used "junction temp" for "doped silicon" transistors in "high reliability" applications about three decades ago. Much higher and the dopants might migrate and reliability went down. Commercial grade devices were running up to 105C, and sometimes 135C even then in some cases.

Since the development of "FET" xistors and higher density designs (smaller switches) 135C was pretty normal for a "design limit" junction temp in "industrial grade" stuff; and higher design limits probably were fairly common in non-critical devices.

These are "junction temperatures," in the inside of the individual devices; but the "bulk temp" of a processor may be pretty close when things get packed close together.

Reliability is better if the temps are kept lower; and since "user machines" seldom have really tight temperature regulation, it's risky to work too close to the limits for normal operation.

I haven't seen anything on recent designs, and the temperature indicated by the program used likely is just an average for the whole processor; but they do run a lot hotter than seems reasonable.

A look at some of the sites popular with people into "overclocking" might give more up to date limits; but some of those guys burn up processors on a regular basis.

John