With NVIDIA publicly listing and therefore officially acknowledging the existence of their 12GB RTX 2060 SKU, many assumed it was just a memory capacity bump but the official specs has made it clear there will be some distinct differences primarily on the CUDA core count.
The Geforce RTX 2060 12GB will sport 2176 CUDA cores versus 1920 on the original 6GB card released in 2019 and will mirror much of the specs of the RTX 2060 SUPER of 2020. Both share the same 2176 CUDA core count but to keep the cards distinct, the RTX 2060 12GB will only have a 192-bit memory bus just like the original RTX 2060. The RTX 2060 Super has a 256-bit bus. Obviously, the memory capacity will be the primary differentiator for the original RTX 2060 6GB and the 12GB version.
Its also worth nothing that NVIDIA has removed the Founders Edition title on their website which leaves us the assume that the RTX 2060 12GB of 2021 will primarily be a partner-only card. This move may serve to fill-in the lower price points that AMD is taking up with their RX 6600 (non-XT). With the RTX 20-series cards still maintaining a higher desirability due to the larger feature set, NVIDIA may be looking to hold their entry-level market further without resorting to an RTX 3050 Ti.