Silicon Motion Launches PCIe 4.0 NVMe SSD Controllers

2020-10-21

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. e3-1220l v3

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)SM2262ENSM2264
Market SegmentMainstream ConsumerHigh-End Consumer
Manufacturing
  Process
28nm28nm28nm12nm
Arm CPU Cores2x Cortex2x Cortex R52x Cortex4x Cortex R8
Error Correction2kB LDPC2kB LDPC2kB LDPC4kB LDPC
DRAM SupportLPDDR3, DDR4
  -XT: None
LPDDR4, DDR4
  -XT: None
LPDDR3, DDR4LPDDR4, DDR4
Host InterfacePCIe 3.0 x4PCIe 4.0 x4PCIe 3.0 x4PCIe 4.0 x4
NAND Channels, Interface Speed4ch
  667 MT/s
4ch
  1200MT/s
8ch
  800MT/s
8ch
  1600MT/s
CEs per Channel48
  -XT: 4
48
Sequential Read2400 MB/s3900 MB/s3500 MB/s7400 MB/s
Sequential Write1700 MB/s3500 MB/s3000 MB/s6800 MB/s
4KB Random Read IOPS300k
  -XT: 280k
500k420k1000k
4KB Random Write IOPS250k500k420k1000k

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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