According to a new report published by 3Dcenter.org, NVIDIA could use GDDR5X memory instead of HBM2 for some of its next-generation Pascal GPUs next year.
GDDR5X memory is claimed to deliver double the prefetch rate and boast of faster total bandwidth of 448 GB/s on a 256-bit bus, compared to 384 GB/s bandwidth offered by GDDR5. HBM2 for reference, can deliver total bandwidth of 512 GB/s on a 2048-bit interface. Creator of GDDR5X memory, Micron claims the newer standard can offer 10-14Gbps signaling rates, up from 6-8Gbps for GDDR5 memory currently.
In case NVIDIA does decide to go with GDDR5X memory on select Pascal GPUs, it makes sense to expect the consumer oriented cards to feature GDDR5X memory while HBM2 may be reserved for enthusiast grade cards such as the GeForce GTX Titan X successor and the high-end Quadro range.