According to the article, there is no departure from their previous generation.
On the contrary, compared with the previous generation, the AM5 socket has more PCIe lanes, because it has 4 additional PCIe lanes, to attach directly to the CPU a Thunderbolt/USB4 controller, for maximum performance.
The changes are strictly in the chipset, which will now be able to provide more PCIe lanes than before, on more expensive motherboards with 2 southbridge chips, but with the price that the extra lanes will pass through an additional PCIe switch, so they will have a greater latency and their throughput can be diminished by congestion, when all the peripherals are active simultaneously.
Nevertheless, with 64 Gb/s links between chips (4 x PCIe 4.0), few peripherals will be fast enough to saturate the links and cause congestion, i.e. typically only the extra SSDs or extra GPUs, besides the primary GPU and the primary SSD, which are attached directly to the CPU.
So the extra SSDs and the extra GPUs should be preferentially attached to the first southbridge chip, not to the second. This is the change about which the users of the new AM5 motherboards must be aware.
On the contrary, compared with the previous generation, the AM5 socket has more PCIe lanes, because it has 4 additional PCIe lanes, to attach directly to the CPU a Thunderbolt/USB4 controller, for maximum performance.
The changes are strictly in the chipset, which will now be able to provide more PCIe lanes than before, on more expensive motherboards with 2 southbridge chips, but with the price that the extra lanes will pass through an additional PCIe switch, so they will have a greater latency and their throughput can be diminished by congestion, when all the peripherals are active simultaneously.
Nevertheless, with 64 Gb/s links between chips (4 x PCIe 4.0), few peripherals will be fast enough to saturate the links and cause congestion, i.e. typically only the extra SSDs or extra GPUs, besides the primary GPU and the primary SSD, which are attached directly to the CPU.
So the extra SSDs and the extra GPUs should be preferentially attached to the first southbridge chip, not to the second. This is the change about which the users of the new AM5 motherboards must be aware.