European online retailers have listed the new Samsung 860 QVO series of SSDs, available in capacities of up to 4TB based on QLC (quad-level cell) NAND.

The new QVO SSDs, which stands for "Quality and Value Optimized SSD", come in a 2.5-inch form factor with SATA III interface and support up to 550/520 MB per second for sequential read/write; 96,000 IOPS random read and 89,000 IOPS random write.

The prices listed online are the following: 1TB 140 euros, 2TB 270 and 4 TB 540 euros (19% VAT included). These prices are much lower than the ones you have to pay for the Samsung Evo family of SSDs.

Availability should be expected sometime next month.

The QLC technology (four-bit) increases the storage density of current 3D NAND chips based on TLC (3-bit), allowing SSD makers to offer more affordable products. However, QLC NAND is obviously inferior in terms of write performance and durability, forcing SSD makers add at SLC write caching in their SSD models. For example, the currently available QLC SSDs such as the Intel 660p oand the Crucial P1 don't perform very well in write tests if they run out of SLC cache.

Questions are also in place regarding the write endurance of QLC NAND. The four bits per cell storage mode of QLC requires discriminating between 16 voltage levels in a flash memory cell. The process of reading and writing with adequate precision is slower than accessing NAND flash that stores fewer bits per cell. The error rates are higher, so QLC SSD controllers apply robusterror correction but still, data retention and write endurance are reduced.

The Samsung 860 QVO SSD is backed by up to 1,440 TBW or a limited 3-year warranty.