I said it already, I have a fan under it already. Its a blacknoise nb eloop b12-2 120mm at 1300RPM on 12V DC, It serves no visible purpose.

I'd say the idle temp is now at 53, better than the 60+ without the fan.

The policy of the temperature control in the ACPI code for fan control is bringing the CPU at this temperature on purpose.

I have verified it because when both cores pass 100 degrees then the fan finally spins at max speed, with a slight hysteresis cycle for progressive down speeding when it "cools" down back below ~90 degrees. Clearly this limit is by design.

It clearly is a limit, but the 100C limit is more of a failsafe limit than one which is meant to be seen under normal operational conditions. Causing the failsafe, 100% fanspeed to manifest frequently could be the result of insufficient cooling / high ambient temperature, a CPU flaw that causes your particular CPU to run hotter than usual, or flawed power delivery. Under normal circumstances, it should never be the 'plan' for a fan to run at 100%, that's a last-ditch effort to restore normal temperatures. I've honestly never seen a cooler have to max itself out, including the machines I've put mild overclocks on. Most coolers you can buy should be able to dissipate all the heat an in-spec CPU can deliver without cracking 85-90% of its cooling capacity. Even the stock cooler, while not great, probably shouldn't be maxing itself out.

You'll sometimes see fans hit 100% because of *over-agressive* cooling, but since you're hitting 100 degrees and then hitting max fanspeed, that's not the intended operational parameters.

Under normal circumstances, it should never be the 'plan' for a fan to run at 100%, that's a last-ditch effort to restore normal temperatures

Recall first that the OP write this is a laptop not a desktop. Then that laptops are usually designed for quiet and reduced power, which means keeping the fans off whenever possible.

In desktops, sure, run the fans all the time, use the power, generate noise. Not a problem.

In laptops, the design is usually to allow them to heat up considerably before turning on the big fans. Passive cooling is preferred, many laptops have large segments of the body acting as a heat sink. Only after the laptop is considerably warm do the power-hungry fans kick on.

For a laptop needing a core of no time, those temperatures are patologic for total.

I would check the fan and medium heat sink from chip. Maybe you should remove contact medium from CPU and check if heat sinking paste is present actualy :( (remembre it hits the temp limit so cpu can by running even undertacted!)

Maybe you should remove contact medium from CPU and check if heat sinking paste is present actualy

On a laptop generally that will void your warranty and potentially break snap-together fastenings of modern cases.

So many of these comments (install a 120mm fan, take it out and install thermal paste, replace the CPU, mount it sideways over a fan) are nonsensical for a laptop.

Laptop processor heat characteristics are radically different from desktop machines.

More seriously, the OP already came back and verified that cooling is working, it just doesn't really kick in until after the alert temperature is hit (which is absolutely normal for laptops trying to save battery):

I have verified it because when both cores pass 100 degrees then the fan finally spins at max speed, with a slight hysteresis cycle for progressive down speeding when it "cools" down back below ~90 degrees. Clearly this limit is by design.

Or maybe the temperature bothers those not familiar with laptops, and maybe he should think about installing water cooling:

Water cooling a laptop? What the world has come to...

On a laptop generally that will void your warranty and potentially break snap-together fastenings of modern cases.

I gess this is less prior than laptop working on normal temperature. As you suggested, it may be late sensoring, but If full cooling is innitiated, it should bring cpu to working on just good temperatures.