[Dylan16807]

High speed I/O pins cost a lot, and GDDR generally has 32 data pins per chip and no way to attach multiple chips to the same pins. So 256 bits and 16GB is hard to exceed by much on that tech. The high end is 384 bits and 24GB.

There is a mode to attach 16 data pins to each GDDR chip, so with some extra effort you could probably double that to 48GB. Or at least 32GB. Maybe this is a valid niche, or maybe there isn't enough demand.

The alternative to this is HBM, which can stack up big amounts, but it's a lot more expensive.