Toshiba puts 64-layer BiCS to work aboard the XG5 NVMe SSD

Toshiba's NAND foundries are spinning up 64-layer versions of the company's BiCS 3D flash memory now, and those chips are marking their first launch aboard a Toshiba storage product today with the XG5 NVMe SSD. This M.2 gumstick will be sold through Toshiba's OEM business, but it could herald interesting developments for the next generation of OCZ client drives.

Before we talk about the XG5 itself, it's worth checking in on the status of Toshiba's BiCS flash. With the move to 64-layer 3D BiCS, Toshiba says its flash now uses a charge-trap architecture (commonly seen in Samsung's V-NAND) instead of the floating-gate structure used by Intel and Micron's 3D NAND. One major benefit of this architectural change is that the drive's controller can now program the TLC BiCS flash in one shot rather than multiple steps. That reduced operational complexity should result in higher performance and lower power consumption versus the company's planar NAND. Toshiba says it's mass-producing 256Gb dies of 64-layer BiCS now, and it's sampling 512Gb dies for testing.

Now, back to the XG5. This PCIe 3.0 x4 SSD takes advantage of 64-layer BiCS to deliver 256GB, 512GB, and 1TB capacities on a single-sided package. The terabyte version of the drive should offer sequential reads up to 3000 MB/s, and sequential write speeds up to 2100 MB/s. Smaller XG5s will offer similar read speeds, but their sequential write numbers will be lower than the terabyte drive's. In a common move for TLC drives, the XG5 implements a pseudo-SLC caching scheme for better write performance. Toshiba didn't have random performance numbers to share ahead of Computex, however.

Toshiba expects to ramp XG5 production in the second half of 2017, so we could start seeing these SSDs in OEM systems around that time. Since this is an OEM product, the company says pricing will vary with supplier agreements. Time will tell whether Toshiba's OCZ client storage division will get a crack at an SSD similar to the XG5.

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