Toshiba PX02SMF080 Internals
The Toshiba PX02SMF080 comes in a 2.5" form factor with a 7mm Z-height. The 1.6TB versions come with a 15mm Z-height. The case is constructed of a lightweight metal alloy and features the relevant branding. The top of the case also holds a recessed series of indentations that function as heat channels. The rear of the case has a metal recessed area, and we noted that there is a square hole, and several round ones, on the bottom of the SSD that exist to allow heat to flow from the interior of the case.
The thermal characteristics of the heat channels become clear when we open the case of the SSD. There are small thermal pads that mate with the NAND and DRAM chips to wick heat away from these components. The small pads are present on both sides of the case, four small thermal pads mate with the top of the controller on one side, and another four connect to the PCB on the other side of the controller. The thermal pads are much smaller than the components, as evidenced by the oily residue they leave on the NAND packages.
We tend to observe the presence of very large thick thermal pads that cover entire banks of NAND in many enterprise SSDs, but in this type of 'open' case, this could impede the internal airflow. The previous generation 6Gb/s SAS SLC MK4001GRZB featured these same type of holes in the case to provide internal airflow.
Interestingly enough, the protrusions on the internal heat channels are indented on the other side of the case. In other SSD designs these type of channels are extended into the interior while the exterior of the case remains flat. This may be due to aerodynamics that allow for more efficient heat transfer on the exterior of the SSD with recessed channels.
The large controller dominates the top of the PCB. There are 8 x 64GB NAND packages (8K page) on both the top and bottom of the PCB with 8 x 64Gb die per package. This gives us 1024GB of raw NAND, though only 745GB is user addressable.
There are two DDR3 DRAM packages near the controller on both sides of the PCB. This provides the eSSD 512MB of DRAM for a fast area of memory to hold LBA mapping tables. The 200GB drive has 256MB, and the 800GB drive carries 1GB of DRAM.
The banks of tantalum capacitors line the top of the PCB on the edge are also on the bottom of the PCB. There are no extra 'pads' for connection of more capacitors on this 800GB eSSD. With many SSDs, the low capacity versions will have fewer capacitors, but leave open pads for manufacturing to add more capacitors to scale with the increased number of components with higher capacity versions. This 800GB SSD is half the capacity of the largest 1.6TB version, and with the larger version having double the thickness at 15mm, it would be safe to assume that the largest PX02SM features a dual PCB design. There is no visible connection hardware for another PCB, so the layout will likely be significantly different for the 1.6TB model.
The etched Toshiba marking has an almost holographic appearance to it, making it hard to photograph. The controller also features a Marvell branding, and a part number that doesn't match with any Marvell controllers we have experience with. The 6GB/s MK4001GRZB predecessor sported a controller with a 88SS9032-BLN2 part number. The TC58NC9036GTC on the 12Gb/s SAS SSD seems to employ a different numbering convention, but the jump from a '9032' to a '9036' version makes sense. Toshiba is holding details of this controller, including core and channel count, close to the chest. The SSD is employing Toshiba proprietary firmware, but other details are scarce.