ludi wrote:I don't have numbers for recent products, but high-performance GPUs have commonly lived on 8-12+ layer PCBs while conventional desktop motherboards have traditionally been in the range of 4-6 layers.
Another problem is that high-performance GPUs tend to produce heat in the same range as a high-performance CPU and tend to have similar cooling requirements, while BGA-packaged chips (including GPUs and chipsets) have a tendency to pop away from a PCB if it flexes too much.
These. Laptops often use daughterboards for the GPU, to have a smaller board done on more layers. Alternately, they'll use a high layer count for the entire laptop mobo, and use the additional routing options to pack things in tighter.
Also, current high end GPUs output much more heat than CPUs, generally 1-10X as much. CPUs are also trending down in heat output while GPUs are holding steady, not decreasing.
I've been here long enough that I think I can forgo a signature.