Hey I forgot to check, but my account already had access to the hbm2e doc. Not much new stuff but a few interesting things:
While products currently available are 2ch per die, vendors are free to design dies with 1, 2, or 4ch/die. So it's still possible to have fully populated channels with only 2 dies.
The additional base logic die is not part of the standard, vendors are free to remove it if they implements that logic into the memory dies. (low cost hbm?)
Die sizes can also be 6gb or 12gb. So it could even do intermediate stack capacites like 18GB or 9GB.
The total number of banks seems to depend on channel size and stack configuration. It's 8, 16, 32, or 48 banks per channel.
The stacks of 8 and 12 are addressed with a stack ID to select one of the group of 4. In practice it's just like more bank select bits. But that means higher stacks have more banks. So maybe better performance from bigger stacks?
While products currently available are 2ch per die, vendors are free to design dies with 1, 2, or 4ch/die. So it's still possible to have fully populated channels with only 2 dies.
The additional base logic die is not part of the standard, vendors are free to remove it if they implements that logic into the memory dies. (low cost hbm?)
Die sizes can also be 6gb or 12gb. So it could even do intermediate stack capacites like 18GB or 9GB.
The total number of banks seems to depend on channel size and stack configuration. It's 8, 16, 32, or 48 banks per channel.
The stacks of 8 and 12 are addressed with a stack ID to select one of the group of 4. In practice it's just like more bank select bits. But that means higher stacks have more banks. So maybe better performance from bigger stacks?