THE FUTURE OF SSDS
Arguably, the future is already here. The two most promising candidates for technology to replace NAND flash as the go-to non-volatile memory technology are thus far Intel’s 3D Xpoint (developed with Micron) and Samsung’s Z-NAND.
Both are available today in real, buyable SSDs. However, neither has achieved anything like mainstream pricing and they remain largely targeted at high-end commercial applications.
3D Xpoint, which forms the basis of Intel’s Optane drives, is a truly revolutionary departure from NAND flash. Instead of creating memory cells out of tiny capacitors as per NAND, 3D Xpoint is a resistance-based technology that uses bulk property change to the cell material to alter its resistance level and so record a memory state.
So, how does Samsung’s Z-NAND compare? Like 3D Xpoint, the big selling point is low latency rather than a leap in sequential throughput. Samsung says its recently announced second-gen Z-NAND SSD, the SZ1735, offers five times lower latency than the best conventional NAND drives, and gets within spitting distance of 3D Xpoint. For comparison, Z-NAND is rated at 12–20μs (microseconds) for read latency, while 3D Xpoint achieves 10μs.
How does Z-NAND do it? Samsung is keeping quiet. It’s known to be a derivative of SLC NAND, perhaps with shorter bitlines and wordlines. With so little to go on, it’s hard to be sure how the competition will play out. It’s not even clear the extent to which Z-NAND is a proprietary tech based on intellectual property that can’t legally be copied.
That’s the greatest worry regarding 3D Xpoint—that Intel will slow-ball development if it ever gains a significant advantage. But even if Z-NAND does end up being a Samsung-only tech, Samsung versus Intel will drive the industry forward faster than just one of them dominating the market for next-gen non-volatile memory, that’s for sure.