NVIDIA internal GPU codenames typically go something like this: first a G (for “graphics” or “GeForce”), then the first letter of the architecture name, and then three digits. The first digit indicates the architectural revision, the second digit marks the chip revision, and then the last digit suggests the specific chip’s expected market

Source: Hot Hardware – Leak Suggests Next-Gen GeForce Blackwell RTX 50 Series May Shake Up Mainstream GPUs