I said that 200cm2 is enough for the chipset while all you did was to display a cooler that has barely this surface yet are claiming that it s enough for 13.5W albeit at 87°C, that s all you stated so far, i see no formal evaluation of yours, hence your tendency to use a derogative language as a pathetic mean to compensate for this lack.
Now getting back to the matter and say 200cm2 sized plate, wich is not as much as what Gygabyte used, and check how much it can dissipate at an ambiant of 300°K (27°C).
The plate has two sides], so its total radiative surface is 400cm2
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Strike one. You calculation starts wrong assuming air renovation for the surface facing the PCB is the same as the surface not facing the PCB. So you dont really have 400cm2 when employing 200cm2 surface on the PCB.
Besides that, do you really realize how big is 200cm2 worth of surface area? A 60x80mm heatsink like the one I showed is already big in ATX standards, and that is less than 1/4 of that.
If you cant fit 200cm2 in a motherboard for starters, all your following napkin math goes to the drain.
The Gigabyte motherboard you like to talk so much about also needs to house at least 2 PCI-E 4 NVME SSDs under that big PCH heatsink. So it's not really only a PCH heatsink only, as the inner surface will eventually get heated by those 3 NVME SSDs whose power consumption is at least the same of current PCI-E 3 NVME SSDs, which is 6-8w each, but judging by the oversized ssd controller heatsinks they are showcasing the new pci-e 4 models, it will likely be more than that.
So we are not talking about only 11w to dissipate, more like +25W because if the PCH gets heated for starters, is because it's running heavy I/O on the PCI-E 4.0 SSDs to begin with. Not even mentioning the fact that we are talking about a 500+ EATX motherboard, plain ATX, mATX and ITX be damned fitting 200cm2 worth of a heatsink so i dont hear a fan, am i right?.
200cm2 heatsink surface area just so you dont hear a fan is plain stupid and we can only thank you are not designing these motherboards as you neglect worst case scenarios regarding air renovation and inner case temperature in your calculations.
Anyway we ll soon see the MB production tested, methink that this chipset TDP frenzy will end as it begun, abruptly...
The chipset tdp frenzy was started by the nostalgics and or lunatics that got triggered by seeing a 50mm fan and went as far as to suggest everyone should copy the Gigabyte's design I linked above like it's a good design practice to trap the heat of your NVME SSDs plus other pcb components under such a massive PCH heatsink plate design.
I certainly couldn't care less, as neither i'm buying a x570 board because ITX x570 seems as cramped as never before and even if it were, the fan spinning is the least of my worries as I know how better small fans got in the noise department the last 10 years and it's MTBF will well beyond what my use case for that motherboard would be.