The processor may not have a throttling function?

Question

AMD

I have a system on an Athlon x4 740 and a Gigabyte F2A88XM-DS2 motherboard. The usual CPU temperature when surfing the Internet is ~ 30-40, and when it works at 100%, it reaches somewhere up to 80 and this has never been a problem. But recently I began to notice that
with a heavy load, the computer began to turn off due to overheating, that is, without trial and throttling, the percentage gains 90 degrees and goes out.

All heatsinks are clean, thermal paste is new, 90% of the time everything is ok, I'm just wondering if AMD really failed to implement the throttling function in 2014 and made such a clown protection mechanism with system shutdown or was it that I was so stupid that I couldn't google normally?