Problem: My Thinkpad used to heat up well over 100C when more than one core was under heavy load.Installing thinkfan allowed to turn off fans when they were not needed, but didn't help otherwise.
Problem source: Besides 0-7 fan speeds, there's also "disengaged" mode which allows to reach ~5800 RPM compared to 4800 for 7. Default thinkfan config and auto mode do not use it for some reason.
Solution: Add a section with "level disengaged" mode to default thinkfan.conf:
(0, 0, 55)
(1, 48, 60)
(2, 50, 61)
(3, 52, 63)
(4, 56, 65)
(5, 59, 66)
(6, 65, 78)
(7, 77, 90)
("level disengaged", 80, 32767)