Hi @albanD
This is not my case, because I am using an IBM AC922 where GPUs are connected to CPUs via NVLINK 2.0. An in addition the memory bandwidth to the CPUs is via 8x DDR4 channels (measured is around 220 GBs).

power9-AC922systemDiagram2_1.png1192×1034

Similar research on this type of HW architecture you ca find here:
http://www.ieee-hpec.org/2018/2018program/index_htm_files/135.pdf 5
Rgds,
FM