Introduction

Zhitai (致钛) is the consumer memory and storage brand of YMTC (Yangtze Memory Technologies), China's largest and most advanced maker of 3D NAND flash. Founded in 2016 and headquartered in Wuhan, YMTC is the company that put Chinese-made NAND on the map: it designs and fabricates its own flash wafers in-house, rather than sourcing them from established players like Samsung, SK hynix, Micron and Kioxia. That makes the TiPlus 9100 one of the few drives on the market where both the brand and the NAND flash inside come from the very same company. It's also a DRAM-less design, which makes a lot of sense right now, with DRAM prices having gone through the roof.

Since this is my first review of a Zhitai drive, I did a bit of digging into the name. In Chinese, it's written 致钛: the first character, 致, roughly means "to deliver" or "to achieve," and the second, 钛, means "titanium"—so the brand is reaching for that titanium visual image—strength, resilience, and premium engineering. This is a China-first brand, and the name was clearly picked to work well in Mandarin rather than English. The international spelling, with its "zh," will be so unfamiliar to most that they'll probably just settle on "zhee-tie"—not unlike how Huawei constantly gets mispronounced. If you'd like to get closer, try the following: picture Jar Jar Binks (yes, I've got Star Wars references for you). Take one "Jar," drop the "a," and you're left with "Jr," then imagine him sitting in a TIE Fighter. That "r" curls your tongue back the same way the Mandarin zh sound does, so "Jr-tie" is pretty close.

Personally, I think "YMTC" is a great name, which rolls off the tongue far more easily—but I suspect they wanted to separate the flash-manufacturing side of the business, while Zhitai is the consumer-oriented name on the retail drives.

YMTC's signature innovation is the Xtacking architecture. Any flash chip has two main parts: the memory cells that store your data, and the control logic that runs them. Normally both are built together on the same piece of silicon, but Xtacking builds them on two separate wafers and then bonds the two whole wafers together with millions of tiny vertical connections. Making each part on its own lets YMTC optimize both, reach higher speeds, and bring new generations to market faster. The pace has been impressive: in just a few years the company went from 64-layer NAND to 128-layer (Xtacking 2.0), 232-layer (Xtacking 3.0), and now the 267-layer Xtacking 4.0 that powers the TiPlus 9100—it's the YMTC X4-9070 3D TLC NAND.

Zhitai doesn't officially specify which controller drives that flash (I asked), but my own analysis strongly suggests that it is a Maxio MAP1802. That's a modern DRAM-less PCIe Gen 5 design fabricated on TSMC 6 nanometer. This combination positions the TiPlus 9100 as an affordable, mainstream model with Gen 5 performance—offering high sequential speeds without the price premium of a DRAM-equipped solid-state-drive. The TiPlus 9100 is offered in 1 TB, 2 TB and 4 TB capacities, with endurance rated at 600 TBW, 1200 TBW and 2400 TBW respectively; we're reviewing the 1 TB model today, which carries a five-year warranty. As a China-first brand it isn't broadly available internationally yet, so pricing comes from the domestic market: at the time of writing, JD.com lists it at 1319 RMB for our 1 TB unit, 2099 RMB for the 2 TB, and 4399 RMB for the 4 TB. These Chinese retail prices include 13% VAT; with that removed—to line up with how US prices are usually quoted—the three capacities work out to roughly $160, $260 and $540, respectively.