For data rates, as in bandwidth per IO pin, distance is really only a secondary factor. HBM memory, for example, runs at substantially lower data rates than GDD

For data rates, as in bandwidth per IO pin, distance is really only a secondary factor. HBM memory, for example, runs at substantially lower data rates than GDDR, yet it sits right next to the GPU die compared to centimeters for the GDDR. And high-speed serial links run at speeds that are an order of magnitude higher than even the internal register files of a CPU.