Microchip recently announced the availability of their second PCIe Gen 5 enterprise SSD controller - the Flashtec 5016. Like the 4016, this is also a 16-channel controller, but there are some key updates:

• PCIe 5.0 lane organization: Operation in x4 or dual independent x2 / x2 mode in the 5016, compared to the x8, or x4, or dual independent x4 / x2 mode in the 4016.
• DRAM support: Four ranks of DDR5-5200 in the 5016, compared to two ranks of DDR4-3200 in the 4016.
• Extended NAND support: 2400 MT/s NAND in the 4016, compared to the 3200 MT/s NAND support in the 5016.
• Performance improvements: The 5016 is capable of delivering 3.5M+ random read IOPS compared to the 3M+ of the 4016.

Microchip's enterprise SSD controllers provide a high level of flexibility to SSD vendors by providing them with significant horsepower and accelerators. The 5016 includes Cortex-A53 cores for SSD vendors to run custom applications relevant to SSD management. However, compared to the Gen4 controllers, there are two additional cores in the CPU cluster. The DRAM subsystem includes ECC support (both out-of-band and inline, as desired by the SSD vendor).

At FMS 2024, the company demonstrated an application of the neural network engines embedded in the Gen5 controllers. Controllers usually employ a 'read-retry' operation with altered read-out voltages for flash reads that do not complete successfully. Microchip implemented a machine learning approach to determine the read-out voltage based on the health history of the NAND block using the NN engines in the controller. This approach delivers tangible benefits for read latency and power consumption (thanks to a smaller number of errors on the first read).

The 4016 and 5016 come with a single-chip root of trust implementation for hardware security. A secure boot process with dual-signature authentication ensures that the controller firmware is not maliciously altered in the field. The company also brought out the advantages of their controller's implementation of SR-IOV, flexible data placement, and zoned namespaces along with their 'credit engine' scheme for multi-tenant cloud workloads. These aspects were also brought out in other demonstrations.

Microchip's press release included quotes from the usual NAND vendors - Solidigm, Kioxia, and Micron. On the customer front, Longsys has been using Flashtec controllers in their enterprise offerings along with YMTC NAND. It is likely that this collaboration will continue further using the new 5016 controller.

Western Digital's FMS 2024 demonstrations included a preview of their upcoming PCIe 5.0 x4 M.2 2280 NVMe SSDs for mobile workstations and consumer desktops. The Gen 5 client SSD market has been dominated by solutions based on Phison's E26 controller. The first generation products launched with slower NAND flash, while the more recent ones have exceeded the 14 GBps barrier by utilizing Micron's 2400 MT/s 232L 3D TLC. Western Digital has been conservative over the last year or so by focusing more on the mainstream / mid-range market in terms of new product introductions (such as the WD Blue SN5000, WD_BLACK SN770M, and the WD Blue SN580). Their SSD lineup is due for an update with Gen 5 drives being sorely missed. The SSDs being demonstrated at FMS 2024 will end up doing just that.

Western Digital's technology demonstrations in this segment involved two different M.2 2280 SSDs - one for the performance segment, and another for the mainstream market. They both utilize in-house controllers - while the performance segment drive uses a 8-channel controller with DRAM for the flash translation layer, the mainstream one utilizes a 4-channel DRAM-less controller. Both drives being benchmarked live were equipped with BiCS8 218-layer 3D TLC.

Western Digital is touting the power efficiency of their platform as a key differentiator, promising south of 7W (performance drive) and 5W (mainstream DRAM-less drive) for the complete SSD under stressful traffic. This makes it suitable for use in mobile workstations, but a good fit for desktops as well.

Demonstrated performance numbers indicate almost 15 GBps sequential reads and 2M+ random read IOPS for the performance drive, and 10.7 GBps sequential reads for the mainstream version. Western Digital might have missed the Gen 5 bus as it started out slowly. However, the technology demonstrations with the in-house controller and NAND indicate that WD has caught up just as the Gen 5 market is about to take off.|

Silicon Motion's SM2320 native USB 3.2 Gen 2x2 controller for USB flash drives and portable SSDs has enjoyed great market success with a large number of design wins over the last few years. Silicon Motion proudly displayed a selection of products based on the SM2320 on the show floor at FMS 2024.

The SM2320 went into mass production in Q3 2021. Since then, the NAND flash market has seen considerable change. QLC is becoming more and more reliable and common, leading to the launch of high-capacity cost-effective 4 TB and 8 TB SSDs. Newer NAND generations with flash operating at higher speeds have also made an appearance.

The SM2320, fabricated in TSMC's 28nm node, supported four channels of NAND flash running at up to 800 MT/s. The new SM2322 uses the same process node and retains support for the same number of flash channels and chip enables (8 CEs per channel). However, the NAND can now operate at up to 1200 MT/s.

The SM2322 also improves the QLC support, thanks to the implementation of a better ECC scheme. While the SM2320 opted for a 2KB LDPC implementation, the SM2322 goes in for a 4KB LDPC solution. The use of a larger region enables extension of the NAND's useful life.

The SM2322 and SM2320 packages are similar in size, and Silicon Motion expects PSSD designs using the SM2320 to adopt the SM2322 with different NAND (higher capacity / speeds) using the same enclosure. Products based on the SM2322 are expected to appear in the market before the end of the year.