even little ambient temperature reduction causes better cooling for the chipset.
For everything inside the case, not just the chipset.
Incorrect. To be fair, I'd have assumed the same. But, a Shim is basically and effectively a DIY-IHS
Not necessarily true.
The best, most efficient transfer of heat occurs with direct, metal to metal contact between the heat sink and the device generating the heat. Adding anything - regardless how efficient it is at conducting heat -
adversely impacts that desired transfer of heat away from the heat sensitive/generating device.
Unfortunately, Man has yet to learn how to create perfection 100% of the time. So there will always be some impurities in the raw materials and imperfections (microscopic pits and valleys) in the mating surfaces of the device and the heatsink. TIM (thermal interface material) is used to fill those microscopic pits and valleys to push out, and keep out any insulating air. Any excess TIM is actually in the way and counterproductive to that heat transfer process.
In a "perfect" world, you would never want to use shims. Shims are often needed to increase the space between two objects so they don't come in contact with each other or to compensate for some other spacing or interference problem.
So a shim is basically ANOTHER imperfect conduit, an extra layer of materials between the mating surfaces the heat if forced to move through before it can escape into the air flow of the case, then out the exhaust vent. And note the more material that heat must move through, the longer it takes to get exhausted out the case. More time is not good.
Shims (and TIM) may be necessary but they certainly are not the ideal solution.
for sure.
