Several Crucial consumer SSDs use QLC (Quad-Level Cell) NAND: the P1, P2, P3, and P3 Plus. Some newer BX500 SKUs also ship with QLC. QLC stores 4 bits per cell across 16 voltage states, compared to 8 states for TLC and 4 for MLC. The tighter voltage margins mean QLC cells degrade faster, tolerate fewer program/erase cycles, and produce higher bit error rates as the drive ages.
For data recovery, QLC complicates the imaging process. PC-3000's Read-Retry function cycles through voltage threshold variations to coax correct data from degraded cells. QLC requires more read-retry iterations than TLC because the voltage windows between valid states are narrower. A cell that stores data correctly at 100 program/erase cycles may produce uncorrectable errors at 300 cycles on QLC, while the same operation on TLC NAND remains reliable past 1,000 cycles.
The DRAMless architecture shared by the BX500, P2, P3, and P3 Plus adds another layer of risk. Without onboard DRAM, the flash translation layer lives in NAND itself, protected only by backup copies. A single power loss event during a NAND write can corrupt both the active and backup FTL, leaving the drive undetectable. Drives with onboard DRAM (MX500, P5 Plus) maintain the FTL in volatile memory and flush it to NAND periodically, reducing (but not eliminating) this risk.