According to VideoCardz, Gigabyte currently sells six distinct GeForce RTX 4070 graphics card models with varying memory configurations on their Thai-language website.
As Nvidia is rumoured to announce the GeForce RTX 4070 in April, it is possible that Gigabyte’s listings are placeholders or errors, as the product’s specifications have not yet been confirmed.
GeForce RTX 4070 with 10GB, 12GB, and 16GB of GDDR6X RAM, including GeForce RTX 4070 Aorus Master 12GB, GeForce RTX 4070 Eagle OC 12GB, GeForce RTX 4070 Gaming OC 10GB, GeForce RTX 4070 Gaming OC 12GB, and GeForce RTX 4070 Gaming OC 16GB, are apparently listed in a Gigabyte game package giveaway
We looked onto the Gigabyte Thai website but were unable to locate this promotion; nonetheless, a user shared it with the VideoCardz crew, so we assume it exists.

GeForce RTX 4070 should be based on the AD104 graphics processor with 5888 CUDA cores working between 1920 MHz and 2475 MHz and a 192-bit memory bus.
Nvidia RTX 40-Series Specifications
GPU | FP32 CUDA Cores | Memory Configuration | TBP | MSRP | |
GeForce RTX 4090 Ti | AD102 | 18176 (?) | 24GB 384-bit 24 GT/s GDDR6X (?) | 600W (?) | ? |
GeForce RTX 4090 | AD102 | 16384 | 24GB 384-bit 21 GT/s GDDR6X | 450W | $1,599 |
GeForce RTX 4080 | AD103 | 9728 | 16GB 256-bit 22.4 GT/s GDDR6X | 320W | $1,199 |
GeForce RTX 4070 Ti | AD104 | 7680 | 12GB 192-bit 21 GT/s GDDR6X | 285W | $799 |
GeForce RTX 4070 | AD104 | 5888 (?) | 12GB 192-bit 21 GT/s GDDR6X | 250W (?) | ? |
GeForce RTX 4060 Ti | AD106 | 4352 (?) | 8GB 128-bit 18 GT/s GDDR6 | 160W (?) | <$500? |
GeForce RTX 3070 | GA104 | 5888 | 8GB 256-bit 14 GT/s GDDR6 | 220W | $499 |
Given that the motherboard must employ 16Gb (2GB) GDDR6X memory chips, the only feasible memory configurations on a 192-bit interface are 12GB (using six ICs) and 24GB (using 12 ICs).
For 10GB, an AD104-based product would need to reduce its memory interface to 160 bits, which is achievable but will reduce memory bandwidth. In contrast, the AD104 lacks a hardware 256-bit memory interface to support a 16GB configuration without an elaborate memory architecture.
At this time, it appears that Gigabyte has listed multiple versions of the GeForce RTX 4070, including a 10GB and a 12GB version, because Nvidia either considers or has examined numerous configurations of the GeForce RTX 4070 product.
In the meanwhile, it is hard for an AD104-based product to support 16GB of memory with its 192-bit memory interface without adopting a complex memory organisation and maybe duplicating the GeForce RTX 970 4GB debacle, at least based on our current knowledge of the AD104.
Despite the possibility that all GeForce RTX 4070 boards with varied memory configurations will be among the top graphics cards on the market, it appears that only the 12GB version will be released.
Still, we will not know until later in the year (perhaps April) at the earliest.