Kioxia's New UFS Storage to Offer Near PCIe Gen4 Performance

Kioxia has announced its next breed of universal flash storage (UFS) devices that use MIPI's M-PHY 5.0 physical layer protocol which significantly increases data transfer rates. The new UFS devices for smartphones, tablets, and ultra-portable notebooks promise to offer performance on par with that of entry-level PCIe 4.0 SSDs.  

Kioxia's new UFS devices will be offered in 128GB, 256GB, and 512GB BiCS 3D NAND configurations. The drives will continue to rely on the UFS 3.1 protocol, but feature the all-new M-PHY 5.0 physical layer that offers up to 23.2 Gbps of raw bandwidth per lane or 46.4 Gpbs of raw bandwidth per two lanes in HS-Gear5 mode (2.9 GB/s or 5.8 GB/s).  

When used with a system-on-chip featuring an appropriate UFS controller that supports HS-G5, the new drives promise an up to 4.4 GB/s sequential read speed (an increase of 90% compared to Kioxia's existing top-of-the-range UFS offerings) as well as an up to 70% higher sequential write speed. In addition, the new UFS devices improve random read and write performance by approximately 35% and 60%, respectively, over previous generation drives. 

Since MIPI's M-PHY 5.0 interface seems to stick to an 8b/10b line encoding, its actual achievable bandwidth should be something like 1.875 GB/s – 3.75 GB/s (for one late and two lanes, respectively). Yet, even at 3.75 GB/s, a dual-lane UFS device supporting MIPI's M-PHY 5.0 physical layer protocol is faster than SSDs with a PCIe 3.0 x4 interface and offers performance comparable to that of SSDs with a PCIe 4.0 x2 interface. 

Since there are no mobile SoCs supporting UFS 3.1 and MIPI's M-PHY 5.0 physical interface, we cannot yet experience the new storage devices for smartphones or notebooks/tablets. Kioxia says that it will initiate sample shipments of its next-generation 256GB UFS storage device on February 25 and will follow up with other models in August.  

It typically takes smartphone makers about 12 – 18 months to develop a smartphone based on a brand-new SoC. That said, expect the first handsets with next-generation UFS 2.1/M-PHY 5.0 storage devices to arrive sometimes in 2023 at the earliest. Perhaps, makers of other devices will adopt the new drives earlier.