Samsung PRO Endurance microSD card.
This analysis works to speculate on the number of layers of TLC and the size of each layer (32GB, 64GB, 128GB). The analysis takes the published endurance specification (green) and calculates the number of GB written for a microSD card with 1,2,3…20 layers. From here we can see then there are patterns (yellow, blue, orange). This gives us a clue as TLC generally has endurance of 1000 writes. We can easily reveal the number of layers and the capacity of each layer that these microSD cards have. The controller will then use this RAW storage and do wear leveling.
For example, if each layer is 128GB (yellow), then
- a 32GB microSD card has 2 x 128GB layers (238.4GB RAW storage)
- a 64GB microSD card has 3 x 128GB layers (357.6GB RAW storage)
- a 128GB microSD card has 5 x 128GB layers (596.0.4GB RAW storage)
This rational provides basis to speculate how the card is able to support the published endurance rating.
My last comment is that physically the three versions of this card might be identical, all having 596GB of RAW storage (5x128GB layers) and the controller is configured to access the quantity of layers which determine the available logical storage. That would streamline manufacturing and drive efficiencies which in turn make it possible to drive down cost.
The table shows the same calculations for the scenarios of each layer being 64GB (blue) and 32GB (orange).
In the interest of full disclosure, I have no information on the architecture of this card beyond Samsung support stating that these cards are TLC and the knowledge that TLC has endurance of approximately 1000 writes. The analysis is pure theory.
