Who wouldn’t want to have one SSD cheap and with high storage capacity? The technology PLC (Penta-Level Cell) for NAND chips that Intel is developing may be the answer to that, but with a possible side effect: depending on the circumstances, the performance of units of the type could drop considerably.
So that you can understand what the different PLC specifications are, we’d like to do a quick recap. Today, the industry works with four types of NAND Flash memory cells: SLC, MLC, TLC and QLC. What differentiates them is the number of bits that each cell can store:
- SLC (Single-Level Cell): 1 bit
- MLC (Multi-Level Cell): 2 bits
- TLC (Triple-Level Cell): 3 bits
- QLC (Quad-Level Cell): 4 bits
The name Penta-Level Cell already gives a clue: the PLC comes to allow five bits to be stored per cell. This means that we can have SSDs with more storage capacity, but without these units having to increase in physical size, which also implies a lower cost per gigabyte.
But there is a limitation: the data storage capacity can even increase, on the other hand, the performance of the SSD in read and write operations tends to drop as the number of bits per cell grows.
There are solutions (or remedies) for this. O Ars Technica for example, some recent Samsung SSDs, such as the Samsung 860 QVO. This line is based on NAND QLC chips (remembering, with four bits per cell), but has SLC cache (one bit per cell), a faster type.
Thanks to this cache, the Samsung 860 QVO 1 TB can reach 520 MB / s (megabyte per second) when writing data. The problem is that if for some reason the cache becomes unavailable (such as when the demand for operations exceeds the capacity of that memory), the write rate can drop to 80 MB / s.
Intel has not yet released all the details regarding its PLC technology, so it is not yet clear what read and write rates the units of the type can achieve, nor the estimated useful life they will have (measured in recording cycles).
There is also no information on when PLC-based SSDs will hit the market, but the Ars Technica points out that, given the likely performance limitations of the technology, it is possible that the first models are intended for data centers or NAS solutions, for example.
Intel is not alone in this endeavor. Companies like Toshiba and Western Digital are also running research on PLC chips.