The P320h comes in a single slot HHHL form factor (Half Height and Half Length). This allows the SSD to fit into slim servers in dense configurations.
Packing all of the NAND and DRAM packages along with the controller into such a slim solution is a daunting task. This is accomplished by utilizing two daughter cards that are connected to the main PCB by two connectors. The large Micron/IDT ASIC controller in the middle of the card is hidden under the large heatsink. This heatsink provides enough cooling to keep the PCIe card cool under the most demanding high-heat scenarios, and requires a standard 300LFM of airflow.
One of the advantages of using SLC flash is its high tolerance for heat. MLC simply cannot withstand the high temperature thresholds that the SLC onboard the P320h can handle easily. This also provides the opportunity for a unique method of packaging the NAND flash packages on the daughter card. The SLC packages are sandwiched very closely to the packages on the main PCB. There is a very small amount of space separating the two PCBs, and MLC would surely overheat in such a densely packaged environment.
SLC can handle the heat, with an easy tolerance of up to 60c, and the card features a throttling mechanism in the event of heat climbing above the maximum threshold. This dynamic throttling can either limit the workload to keep the device cool enough for safe operation, or shut the card down entirely.
The daughter boards are fastened to the main PCB by connectors that allow the cards to be easily detached. We can see the banks of Micron 34nm SLC ONFI 2.1-compliant NAND. There are a total of 64 packages on the drive, for a total of 1TB of raw NAND. There are four packages per die on the 350GB drive, and double the density for the 700GB drive, with eight packages per die. Five of the banks of Micron DRAM are to the left of the large Micron/IDT controller, and four more DRAM packages are contained on the rear of the drive. This leaves a total of 2.25GB of DRAM available to the device.
The two daughter cards hold four packages per side, for a total of eight per card.
Here we can observe the connector that mates the cards to the main PCB. These daughter cards are secured to the main PCB with thick fasteners that also have Loctite on the threads to function well in high vibration environments. The rear of the card holds the remaining NAND packages and the remainder of the DRAM resides under the left edge of the sticker.