Comment by dumah

Radiation at desirable operating temperatures is a relatively weak means of heat transport, hence spreaders.

Only a big power-efficient chip like M2 Ultra could survive if it could _only_ radiate from one side of the wafer into CMB.

The rest of the silicon will become molten at 100% TDP: H100, Xeon, Core, EPYC, Ryzen.

Most would be over 400C at 1% TDP.

Conduction and convection are linear or close and are effective at desirable temperatures, whereas thermal radiation is quartic and highly convex.