Silicon Motion Launches PCIe 4.0 NVMe SSD Controllers

Silicon Motion has announced the official launch of their first generation of PCIe 4.0-capable NVMe SSD controllers. These controllers have been on the roadmap for quite a while and have been previewed at trade shows, but the first models are now shipping. The high-end SM2264 and mainstream SM2267/SM2267XT controllers will enable consumer SSDs that move beyond the performance limits of the PCIe 3.0 x4 interface that has been the standard for almost all previous consumer NVMe SSDs.

The high-end SM2264 controller is the successor to Silicon Motion’s SM2262(EN) controllers, and the SM2264 brings the most significant changes that add up to a doubling of performance. The SM2264 still uses 8 NAND channels, but now supporting double the speed: up to 1600MT/s. The controller includes four ARM Cortex R8 cores, compared to two cores on SMI’s previous client/consumer NVMe controllers. As with most SSD controllers aiming for the high end PCIe 4.0 product segment, the SM2264 is fabbed on a smaller node: TSMC’s 12nm FinFET process, which allows for substantially better power efficiency than the 28nm planar process used by the preceding generation of SSD controllers. The SM2264 also includes support for some enterprise-oriented features like SR-IOV virtualization, though we probably won’t see that enabled on consumer SSD products. The SM2264 also includes the latest generation of Silicon Motion’s NANDXtend ECC system, which switches from a 2kb to 4kB codeword size for the LDPC error correction.

The SM2264 controller will be competing with in-house controllers used by Samsung and Western Digital for their flagship consumer SSDs, and against the upcoming Phison E18 controller. Phison’s E16 controller was the first consumer PCIe 4.0 controller to hit the market, but is now being outclassed by a second wave of PCIe 4.0 controllers that come much closer to using the full potential of a PCIe 4.0 x4 interface. The SM2264 controller is currently sampling to drive vendors, but we don’t have an estimate for when products will be hitting the shelves.

Silicon Motion Client/Consumer NVMe SSD Controllers
  SM2263(XT) SM2267(XT) SM2262EN SM2264
Market Segment Mainstream Consumer High-End Consumer
Manufacturing
Process
28nm 28nm 28nm 12nm
Arm CPU Cores 2x Cortex 2x Cortex R5 2x Cortex 4x Cortex R8
Error Correction 2kB LDPC 2kB LDPC 2kB LDPC 4kB LDPC
DRAM Support LPDDR3, DDR4
-XT: None
LPDDR4, DDR4
-XT: None
LPDDR3, DDR4 LPDDR4, DDR4
Host Interface PCIe 3.0 x4 PCIe 4.0 x4 PCIe 3.0 x4 PCIe 4.0 x4
NAND Channels, Interface Speed 4ch
667 MT/s
4ch
1200MT/s
8ch
800MT/s
8ch
1600MT/s
CEs per Channel 4 8
-XT: 4
4 8
Sequential Read 2400 MB/s 3900 MB/s 3500 MB/s 7400 MB/s
Sequential Write 1700 MB/s 3500 MB/s 3000 MB/s 6800 MB/s
4KB Random Read IOPS 300k
-XT: 280k
500k 420k 1000k
4KB Random Write IOPS 250k 500k 420k 1000k

For the more mainstream product segments, Silicon Motion’s SM2267 and SM2267XT controllers are the replacements for the SM2263 and SM2263XT. These will help bring entry-level NVMe performance up to about the level that used to be standard for high-end PCIe 3.0 SSDs. The SM2267XT is the DRAMless variant of the SM2267 and also has half as many chip enables (CEs), which allow for a much smaller package size suitable for use on small form factors like M.2 2230. The SM2267(XT) controllers are still manufactured on the cheaper 28nm process. The SM2267 and SM2267XT controllers are in mass production and the first products using those parts have also entered the supply chain: we already have a sample of ADATA’s Gammix S50 Lite with the SM2267 controller on our test bench.

The SM2267 will be competing against a mix of older 8-channel controllers like the Phison E12, and newer 4-channel solutions as seen in the SK hynix Gold P31. We expect this to be the most important consumer SSD product segment going into 2021 as these drives will not carry the steep price premium currently seen on high-end 8-channel PCIe 4.0 SSDs, and they’ll still be plenty fast for almost all use cases. The DRAMless SM2267XT variant will be competing against controllers like the Phison E19T for entry-level NVMe SSDs that carry little or no price premium over SATA drives. These low-cost NVMe controllers are also increasingly popular for portable SSDs; the performance increases of the SM2267XT over the SM2263XT will not matter for drives using 20Gb/s USB to NVMe bridge chips, but will be helpful for Thunderbolt SSDs.

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