> If you “folded” the GPU over the CPU to save height I would think that would be worse than today for heat.
Why? Cooling would be far better: the CPU and GPU heatsinks would both face outward from the center and receive clean front-to-rear airflow. Thus, looking down from above:
The power supply and power connectors are on the bottom. Another PCB lays flat on top to host open PCI-E slots, NVMe, whatever, connected 90 deg. to the CPU PCB with one PCI-E slot interconnect. All interconnects are short. Air flow is simple and linear. The CPU/GPU Heatsinks are large and passive: you only need intake fans.
I've been refining this. I'm actually learning FreeCAD to knock out a realistic 3D model.
One obvious change: run the CPU/GPU interconnect across the bottom: existing GPU designs could be used unmodified (or enhanced with only a new heatsink) and the 16x PCI-E lanes for the GPU would be easier to route off the CPU PCB.
There are virtually no significant differences between the motherboard layout IBM promulgated with original IBM PC (model 5150) in 1981 and what we have today. That machine had a 63W power supply and no heatsinks or fans outside the power supply. The solution to all existing problems with full featured, high power desktop machines is replacing the obsolescent motherboard design with something that accommodates what people have been building for at least 20 years now (approximately since the Prescott era and the rise of high power GPUs.)
Why? Cooling would be far better: the CPU and GPU heatsinks would both face outward from the center and receive clean front-to-rear airflow. Thus, looking down from above:
The power supply and power connectors are on the bottom. Another PCB lays flat on top to host open PCI-E slots, NVMe, whatever, connected 90 deg. to the CPU PCB with one PCI-E slot interconnect. All interconnects are short. Air flow is simple and linear. The CPU/GPU Heatsinks are large and passive: you only need intake fans.