https://www.tomshardware.com/news/samsung-gddr6w-doubles-performance-and-capacity
"Samsung has introduced its all-new type of GDDR6 memory that doubles the DRAM package's capacity and increases interface width to double its peak bandwidth."
It's got twice as many dies inside the package, with a more advanced 3D interconnect, has two physical interfaces to get the double bandwidth, and is thinner than regular GDDR6, so it should be easier to cool. They claim it approaches the bandwidth of HBM2E.
"Samsung has introduced its all-new type of GDDR6 memory that doubles the DRAM package's capacity and increases interface width to double its peak bandwidth."
It's got twice as many dies inside the package, with a more advanced 3D interconnect, has two physical interfaces to get the double bandwidth, and is thinner than regular GDDR6, so it should be easier to cool. They claim it approaches the bandwidth of HBM2E.