The Flash Memory Summit is underway in Santa Clara, CA this week, and NAND news is likely to fly hard and fast. For its part, Samsung is taking the wraps off what it calls the first quad-level-cell, or QLC, SSD for consumers. The company says these drives are in mass production now.
This as-yet-un-catchily-named 4-TB drive uses Samsung's latest 1-Tb, 64-layer QLC V-NAND chips to reach its high capacity. Samsung says the drive has 32 of those chips inside, all connected to what sounds like a TLC SSD controller, to deliver sequential read speeds of 540 MB/s and sequential write speeds of 520 MB/s—no worse than the average TLC SATA drive. The magic mayo in this flash sandwich is apparently Samsung's TurboWrite caching scheme.
That claimed-TLC-equivalent performance is important in a consumer drive because the challenge of actually reading and writing data from a QLC cell has the potential to degrade performance. The first QLC drives we've seen are accordingly targeted at read-heavy workloads where density is more important than all-around performance.
QLC NAND also presents endurance problems for write-heavy workloads, and Samsung's warranty for these drives suggests that could still be a potential point for concern with its upcoming QLC products. The company only plans to back these drives with three years of warranty coverage, compared to five years for the 860 EVO and 860 Pro drives.
For the kinds of read-heavy mass-storage SSDs PC enthusiasts want for large game libraries, for just one example use case, these Samsung QLC drives could be just the ticket. Samsung plans to introduce several QLC consumer drives this year in 1-TB and 2-TB capacities to go with the aforementioned 4-TB drive. All of these bit buckets will use the 2.5″ form factor. Pricing and retail availability weren't discussed in Samsung's press release.