Not necessarily. A flexible interconnect would allow the GPU to be planar with the MB; just bend it 180 degrees. Now your GPU and CPU can have coolers with good airflow instead of the farcical CPU (125mm+ tall heatsinks...) and GPU cooling designs (three fans blowing into the PCB and exhausting through little holes...) prevailing today.
My idea is to separate the whole CPU complex (the CPU and heatsink, RAM slots, VR, etc.) from everything else and use short, flexible interconnects to attach GPUs, NVMe and backplane slots to the CPU PCB, arranged in whatever scheme you wish.
I was kind of hoping doing it that way would let you put big CPU style coolers on the GPU parts with a lot more height than a 1x or 2x expansion slot.
If you “folded” the GPU over the CPU to save height I would think that would be worse than today for heat.
Maybe I’ve got this backwards. Give up on PCIe, or put it above the rest of the motherboard. The one GPU slot, planar to the motherboard, stays below. Basically my previous idea flipped vertically.
The other PCIe slots don’t need to run as fast and may be able to take the extra signal distance needed. The GPU could secure to the backplane (like my original idea) but would have tons of room for cooling like the CPU.
> 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.)
Not necessarily. A flexible interconnect would allow the GPU to be planar with the MB; just bend it 180 degrees. Now your GPU and CPU can have coolers with good airflow instead of the farcical CPU (125mm+ tall heatsinks...) and GPU cooling designs (three fans blowing into the PCB and exhausting through little holes...) prevailing today.
My idea is to separate the whole CPU complex (the CPU and heatsink, RAM slots, VR, etc.) from everything else and use short, flexible interconnects to attach GPUs, NVMe and backplane slots to the CPU PCB, arranged in whatever scheme you wish.