Why it matters: China has been trying to bolster its semiconductor industry for years in an effort to become self-sufficient and more competitive on the global market. Development has been slow on the CPU side of things, but it looks like the country's NAND champion is quickly closing the gap on flash storage when compared to industry giants like Samsung, Micron, and SK Hynix.

Back in July, Chinese media outlets reported that Yangtze Memory Technologies Co (YMTC) was getting ready for mass manufacturing of 128-layer 3D NAND memory, which is considered the pinnacle of domestic flash memory development and key to addressing the high demand for consumer-grade solid-state storage in the region.

The Wuhan-based company may be China's NAND champion, but it's a relatively small player in the grand scheme of things. For reference, Intel, Micron, Kioxia, Samsung, SK Hynix, and Western Digital account for a combined 97 percent of the NAND market, so it won't be easy for YMTC to compete with these memory giants. It also doesn't help that parent company Tsinghua Unigroup has been having financial difficulties and is currently looking for a generous cash infusion to stay afloat.

According to a report from Tech Insights, YMTC has indeed started mass-producing the new memory chips. The IP and tech intelligence firm managed to take a closer look at Asgard's new AN4 1-terabyte SSD, which is based on the YMTC's 128-layer NAND. Although the Chinese company calls it "3D NAND," it should be noted that a more accurate term would be 2.5D NAND, as it leverages Xstacking 2.0 hybrid bonding technology to essentially glue together two separate dies – one for the TLC NAND array and another for the CMOS peripheral circuitry.

That said, the new SSD is no slouch, with sequential read speeds of up to 7,500 megabytes per second and write speeds of up to 5,500 megabytes per second. As you may have guessed, the Asgard is a PCIe 4.0 SSD, and these speeds are achieved over an x4 interface thanks to the InnoGrit IG5236 controller. This is the same controller used in the Plextor M10P SSD, and coupled with YMTC's 128-layer NAND, it can achieve over 1.2 million IOPS in 4K read workloads and 900,000 in 4K write workloads.

NAND Technology YMTC 128L Xtacking Samsung 128L V-NAND Micron 128L CuA CTF SK Hynix 128L 4D PUC
Device Asgard AN4 1TB Samsung EVO 870 1TB Crucial BX500 480GB SK Hynix Gold P31 1TB
Capacity per die 512 Gb 512 Gb 512 Gb 512 Gb
Die size 60.42 sq. mm 74.09 sq. mm 66.02 sq. mm 63 sq. mm
Memory density 8.48 Gb per sq. mm 6.91 Gb per sq. mm 7.76 Gb per sq. mm 8.13 Gb per sq. mm

It's also worth noting that YMTC's new 128-layer NAND memory has almost double the density of previous designs based on the initial version of its Xstacking tech. More importantly, the 8.48 Gb per square millimeter in storage density is higher than that achieved by Samsung, Micron, and SK Hynix using comparable 128-layer TLC NAND designs. These companies have largely moved on to more advanced designs, but it looks like China is quickly closing the gap.

YMTC has also been working on a successor to Xstacking 2.0, which will allow the company to make high-capacity QLC 3D NAND memory with a capacity of 1.33 Tb per die. However, development on 128-layer QLC NAND has been slow, and the company says it has yet to achieve better yields needed for mass manufacturing of the new memory chips. In the meantime, YMTC is scrambling to increase production to 100,000 wafer starts per month by the end of the year and is not affected by the recent energy crunch in China.

Overall, this development is much more impressive than what's been going on with x86 and Arm-based CPU development in the region. That said, Zhaoxin's x86 processors are slowly creeping into consumer products, and Huawei's HiSilicon subsidiary has been quietly pushing its custom Arm-based Kunpeng silicon to both consumers and data center clients. As for YMTC, it has an extensive list of clients, mainly Chinese phone makers and SSD manufacturers. With its new 128-layer NAND, the Wuhan-based chipmaker intends to attack the data center market in the near future.