The Penta-level cell flash (PLC) may be the next logical step for SSDs, but Western Digital does not believe the technology is ready for prime time until at least 2025 (via Tom & # 39; s Hardware). The reason for the delay is that newer, more powerful drivers will be needed to make the change to the PLC worthwhile.
The most popular storage technology currently used by SSDs is the three-level cell flash (TLC), which uses eight voltage levels to store three bits per cell. The four-level cell flash (QLC) uses 16 voltage levels to store four bits per cell, but requires advanced error correction along with wear leveling and over-supply to maximize resistance.
The 32 voltage levels required for the PLC flash will require even better error correction, which in turn requires faster processors in the center of the controllers. This new flash technology will also require more oversupply, error correction, and wear leveling to make the 25% increase in capacity worthwhile.
The problem is not the flash technology itself, but what happens to a modern SSD and this can undermine the value proposition of the PLC itself. In the same way that QLC flash memory has not resulted in cheaper and more capable SSDs, despite the promise: these drives need elaborate caches to mask the underlying performance of the flash technology used.
We may see PLC SSDs before 2025, as the computer industry has a history of solving such problems. And this could cause SSDs to offer hard drive capacity levels, hopefully, without offering hard drive performance levels. However, it does not seem to be just an easy step to switch to Flash PLC.