Although consumer SSDs based on Phison’s PS5026-E26 controller have been on the market for almost a year and a half now, the class-leading drives still come with a distinct price premium. This is partially because it’s still one of the only options for a PCIe 5.0 SSD. However, the situation is likely to change in the coming quarters, as SSDs based on Phison’s PS5031-E31T controller are on the horizon, with at least one Phison customer showcasing an E31T drive on the Computex show floor.
Phison’s PS5031-E31T controller uses two Arm Cortex-R5 cores accelerated by the Andes N25 CoXProcessor, much like its bigger sibling, the Phison PS5026-E26. However, their major hardware similarities end there. The new E31T controller is a DRAM-less controller with four NAND channels (16 CE targets) manufactured using one of TSMC’s 7nm processes, in contrast to the E26, which is an eight-channel controller produced on TSMC’s 12nm production node.
Besides reducing memory channels and eliminating DRAM to lower costs, the E31T also incorporates a couple of new features, being nearly two years newer. Specifically, the E31T sports Phison’s 7th Generation LDPC error correction technology, upgrading from the E25’s 5th-gen LDPC.
| Phison NVMe SSD Controller Comparison | |||||||||
| E31T | E27T | E21T | E26 | E18 | |||||
| Market Segment | Mainstream Consumer | High-End Consumer | |||||||
| Manufacturing Process | 7nm | 12nm | 12nm | 12nm | 12nm | ||||
| CPU Cores | 2x Cortex R5 | 1x Cortex R5 | 1x Cortex R5 | 2x Cortex R5 | 3x Cortex R5 | ||||
| Error Correction | 7th Gen LDPC | 5th Gen LDPC | 4th Gen LDPC | 5th Gen LDPC | 4th Gen LDPC | ||||
| DRAM | No | No | No | DDR4, LPDDR4 | DDR4 | ||||
| Host Interface | PCIe 5.0 x4 | PCIe 4.0 x4 | PCIe 4.0 x4 | PCIe 5.0 x4 | PCIe 4.0 x4 | ||||
| NVMe Version | NVMe 2.0 | NVMe 2.0 | NVMe 1.4 | NVMe 2.0 | NVMe 1.4 | ||||
| NAND Channels, Interface Speed | 4 ch, 3600 MT/s |
4 ch, 3600 MT/s |
4 ch, 1600 MT/s |
8 ch, 2400 MT/s |
8 ch, 1600 MT/s |
||||
| Max Capacity | 8 TB | 8 TB | 4 TB | 8 TB | 8 TB | ||||
| Sequential Read | 10.8 GB/s | 7.4 GB/s | 5.0 GB/s | 14 GB/s | 7.4 GB/s | ||||
| Sequential Write | 10.8 GB/s | 6.7 GB/s | 4.5 GB/s | 11.8 GB/s | 7.0 GB/s | ||||
| 4KB Random Read IOPS | 1500k | 1200k | 780k | 1500k | 1000k | ||||
| 4KB Random Write IOPS | 1500k | 1200k | 800k | 2000k | 1000k | ||||
Phison refers to its E31T platform as ‘the first mainstream 10 GB/s platform,’ indicating high performance for upcoming affordable PCIe Gen5 SSDs. Regarding random performance, 1.5M IOPS per second is comparable to some enterprise-grade PCIe Gen4 SSDs.
Meanwhile, a Silicon Power ad at Computex reveals the company’s aim to achieve 12 GB/sec with its “US85” drive. Achieving this with 4 NAND channels would require pairing the controller with cutting-edge 3200 MT/sec NAND. Although unusual for the mainstream, cost-effective status of the E31T controller, the savings on the controller could be reinvested into the NAND on the drive. More importantly, with 12 GB/sec read and write speeds, Silicon Power’s US85 SSD can compete with earlier E26-based drives still on the market, elevating this product to a new level. However, Silicon Power will need to secure enough fast 3D NAND to meet demand.
Both Phison and Silicon Power expect E31T to start shipping in Q4, so by the start of next year, mainstream SSDs should see a substantial speed boost. 
