Metal Messiah from DSOGaming writes: “The GeForce RTX 3090 graphics card is being listed on the Micron website with 12GB GDDR6X memory, so we can expect the bandwidth to be between 912 to 1008 GB/s.”
Source: N4G PC MICRON confirms that the NVIDIA Ampere RTX 3090 card will get 21Gbps GDDR6X memory