Micron Technology has begun mass production of GDDR6X memory chips rated at 21 Gbps and 24 Gbps, which will be utilized solely by NVIDIA in its next-generation RTX 40-series "Ada" graphics cards. 

GDDR6X is a GDDR6 variant co-developed by NVIDIA and Micron that uses PAM4 signaling to boost data speeds. Depending on the graphics card model, NVIDIA will use 8 Gbit (1 GB) or 16 Gbit (2 GB) density memory chips. 

NVIDIA's high-end series is claimed to utilise both 21 and 24 Gbps speeds. According to speculations, NVIDIA will use 21 Gbps GDDR6X modules for three of the high-end SKUs: RTX 4090, 4080, and 4070. Simultaneously, speculations suggest that the claimed flagship product, either a professional workstation GPU or a Ti , will have 24 Gbps modules.

Micron is developing 21Gbps and 24Gbps GDDR6X memory chips.