A Closer Look At The SM951 SSDs
Both of the drives we're testing today share the same layout, controller and DRAM. The main difference between them is that the number of dies per package doubles on the 256GB SM951.
All Samsung SM951 SSDs ship in the M.2 2280 form factor. The firmware installed on both of our samples is BXW25000. The Lenovo model's firmware is BXW22L00.
The two lower-capacity SM951s use just two NAND flash packages.
The smaller drives are also single-sided; all of their surface-mount components are on one side. The 512GB model is double-sided. This can be important, since some companies use a single-sided connector that sits closer to the motherboard.
All three capacities employ the same Samsung UBX controller.
The two lower-capacity models use the same DRAM, while the 512GB model ships with twice as much DRAM to cache page table data.
The flash is the same 1xnm across all three models. Only the number of dies per package increases alongside capacity. The two drives we're testing today sport two packages. We suspect Samsung uses quad-plane flash, and that is how it manages to reach this level of performance.