Introduction
We’ve got an exciting early look at what kind of PCIe Gen5 performance the new Phison E28 controller will deliver to M.2 NVMe SSDs with some benchmarks and hands-on testing. Phison sent us its reference design SSD based on its new PS5028-E28 controller for PCIe 5.0 (Gen5) NVMe SSDs.
We’ve got a first look at the performance of the new Phison E28 controller, based around a 2TB PCIe 5.0 x4 NVMe M.2 SSD with KIOXIA BiCS8 218-layer TLC 3D NAND Flash. In this preview today, we’ll test the Phison E28 controller-based SSD and see what kind of performance might be delivered from partner models when SSDs using the Phison E28 controller become available. PCIe 5.0 Gen5 SSDs just got a whole lot better.
Normally, about now we would be talking about pricing and what models are offered, but the specific SSD we have today is a pre-release “reference model” design sporting the new Phison E28 controller directly from Phison. As a pre-release reference design, this is not a model that will specifically be sold, but is rather a platform to promote with the retail partners and to demonstrate the performance, features, and testing platform for partners to design cooling solutions.
As such, this SSD is also using pre-release firmware, close to the production version, and Phison is about 30-45 days from releasing a fully optimized version to its partners. Production firmware can improve performance, specifically read latency at low queue depths, as well as endurance, power, and background garbage collection. That said, you’ll be amazed at the already great performance.
If you haven’t heard about Phison, well, where have you been? Phison has been a well-known and popular solution for NAND flash technologies in high-performance storage for a long while. Phison is currently celebrating 25 years in the OEM, ODM, Enterprise, and Consumer spaces.
We have reviewed many SSDs in our time that are based on Phison controllers. The Phison E28 is the next evolution of controllers, replacing the E26. We have reviewed some Phison E26 based SSDs, notably the MSI SPATIUM M580 FROZR 2TB SSD, as does the MSI SPATIUM M570 PRO FROZR 2TB SSD, and the CORSAIR MP700 PRO with Air Cooler 2TB SSD. We had found the Phison E26 controller to simply provide the best PCIe Gen5 NVMe SSD performance out there, so it is very exciting to see what the Phison E28 can do in comparison!
Phison PS5028-E28 Reference Design 2TB SSD
We actually saw the Phison E28 controller-based SSD in person back at CES 2025 this past January. Phison was previewing the E28 controller at the beginning of this year. As we noted then, one of Phison’s goals with the E28 controller is to reduce power usage and heat generation compared to the previous E26 controller. Phison has now moved to TSMC’s 6nm processor node to accomplish this for the E28 controller.
At its heart, the Phison E28 is a 3-core architecture featuring two proprietary Phison CoX-processors in an 8-channel 32 CEs configuration and supports the NVMe 2.0 protocol and PCIe 5.0 x4 (PCIe Gen5x4) interface. It can operate up to 4200MT/s and capacities as large as 32TB, and a dedicated DRAM buffer as well, with LPDDR4/4X and LPDDR5/5X support. You’ll see consumer SSD drives in the 1TB, 2TB, and 4TB storage capacities using this controller. The controller was also built for enterprise workloads in the E28 DC, and an AI variant as well, with onboard data processing for use with Phison’s aiDAPTIV+ technology.
The Phison E28 controller supports many modern flash management functions, power management, and security features. It supports Dynamic Wear Leveling, Bad Block Management, TRIM, SMART, Over-Provision, and Firmware Updates. It supports power management modes PS0/PS1/PS2/PS3/PS4, APST, ASPM and L1.2. Other features include SRAM ECC protection, Thermal Throttling, LDPC + RAID ECC, SmartRefresh, Drive Log, and support of TCG Pyrite.
The Phison E28 controller is all about reduced power and heat. The typical or average power is rated at 8.5W, and L1.2 < 5mW. Typical operating temperature is up to 70 °C for the high-end range in operation. MTBF is 1.5 million hours. In the pictures above, if you are wondering what the two chips are on the backside near the latch area, those are the PCIe Power and PCIe Signal chips.
| Sequential | Sequential | Random | Random | ||
|---|---|---|---|---|---|
| Capacity | Flash Structure | Read MB/s | Write MB/s | Read IOPS | Write IOPS |
| 1000GB | 512GB x 2, 8CE | 14900 | 13500 | 1300K | 2800K |
| 2000GB | 1024GB x 2, 16CE | 14900 | 14000 | 2500K | 3000K |
| 4000GB | 2048GB x 2, 16CE | 14900 | 14000 | 2600K | 3000K |
The particular reference design SSD Phison has provided as the E28 test-bed is in the standard M.2 2280 format size. On board, it has up to 2 pieces of BGA308 flash NAND at 2400MT/s and a LPDDR4x dedicated DRAM buffer from SK-Hynix. The 3D NAND Flash is KIOXIA BiCS8, KIOXIA’s 8th generation BiCS 218-layer 3D NAND Flash, you can read the specifications here. The sequential read performance is rated at 14,900MB/s, and the sequential write performance is rated at up to 14,000MB/s. Above, you can see the performance metrics based on the flash structure and capacity using BiCS8 1024Gb TLC 2400Mbps NAND flash.
The Phison PS5028-E28 Reference Design 2TB SSD is a bare drive, and all the chips are on one side, so only one side needs to be cooled for our testing. In our test system, we did not install a third-party heatsink; rather, we are using an active fan at a very high speed to keep the controller cool for testing purposes. Manufacturer-built SSDs will either employ their own cooling mechanisms or sell the drives bare, which means you’ll want to use your included motherboard M.2 heatsink, which should work fine with this cooler running, lower-power SSD. It should also be noted that the Phison E28 controller is well-suited for notebook use and can deliver the 14GB/s performance in notebooks thanks to its efficiency.