NVIDIA has reduced the PCI Express interface to eight lanes for both the AD106 and AD107 GPUs. On the one hand, the reason lies in saving the area of the chip. On the other hand, the narrow interface consumes less power in laptops.
In the case of PCI Express 4.0, eight lanes instead of 16 do not lead to noticeable disadvantages, since they provide a throughput of 15.754 GB / s. But if the video card is installed in the old standard PCI Express 3.0 slot, the bandwidth drops by half to 7.877 GB / s.
In comparison of PCIe 3.0 x8 and PCIe 4.0 x8, the difference in benchmarks was noticeable, but gamers are unlikely to feel it in practice.

Although the AD106 and AD107 GPUs are connected via eight lines, video card manufacturers still released models with a PCB and a slot containing 16 physical lines. Even if only eight of them were used.
Palit was the first manufacturer to cut the slot physically. So far, only these short-slot GeForce RTX 4060 graphics cards are known.