The recent excitement in the client SSD space is rightfully at the forefront of Gen 5. However, cooling requirements are making it difficult for vendors to bring effective M.2 NVMe Gen 5 SSDs to market. In that sense, it looks like the 4th Gen M.2 SSD will continue to have a much longer runway than previously estimated. To better serve that market segment, Silicon Motion is introducing a new addition to his line of PCIe 4.0 capable NVMe SSD controllers. The company’s roadmap isn’t too secret as the Gen 5 client controller is expected to arrive in Q4 2023. However, today is the official launch date for his SM2268XT. This is the 3rd generation of his DRAM-less Gen 4 SSD controller, intended to play in the entry-level segment in terms of price, but move to the high-end in terms of performance.
Key updates of SM2268XT over SM2267XT and SM2269XT include increased data rate per channel from 1600 MT/s to 3200 MT/s and support for the latest 2xx layer 3D TLC (and QLC) from various flash vendors That’s what I did. The new controller also brings support for some NVMe 2.0 features (compared to NVMe 1.4 on SM2267XT and SM2269XT). Similar to SM2269XT, the codeword size of SM2268XT’s LDPC engine is also 4KB (compared to SM2267XT’s 2KB). The move to the 12nm process will also improve power efficiency.
THE SM2268XT competes with Western Digital’s in-house controllers (like the one used in the WD_BLACK SN770), the upcoming Phison E21T, and InnoGrit’s RainierQX IG5220. The SM2268XT’s claimed performance numbers at all four corners lead its class.
| Silicon Motion Client/Consumer Gen 4 NVMe SSD Controller | |||||
| SM2264 | SM2267 | SM2267XT | SM2269XT | SM2268XT | |
| Market segment | high end consumer | mainstream consumer | |||
| manufacturing industry process |
12 nm | 28 nm | 12 nm | ||
| arm CPU core | 4x ARM Cortex R8 | 2x ARM Cortex R5 | 2x ARM Cortex R8 | ||
| error correction | 4KB LDPC | 2KB LDPC | 4KB LDPC | ||
| DRAM support | DDR4, LPDDR4(X) | DDR3, DDR3L, LPDDR3, DDR4, LPDDR4 | None / HMB | ||
| host interface | PCIe 4.0 x 4 | ||||
| NAND channel, interface speed | 8ch 1600MT/s |
8ch 1200MT/s |
4ch 1200MT/s |
4ch 1600MT/s |
4ch 3200MT/s |
| CE per channel | 8 | 8 | Four | ||
| Sequential read | 7500MB/s | 3900MB/s | 3500MB/s | 5100MB/s | 7400MB/s |
| Sequential write | 7000MB/s | 3500MB/s | 3000MB/s | 4800MB/s | 6500MB/s |
| 4KB random read IOPS | 1.3 million | 500K | 500K (HMB) / 200K (without HMB) | 900K | 1.2 million |
| 4KB random write IOPS | 1.2 million | 500K | 500K | 900K | 1.2 million |
The company says the SM2268XT is currently sampling to major customers, indicating an imminent launch of an SSD based on it. Expect the usual suspects such as ADATA to announce SSDs based on the new controllers soon.
