Intel announced that it started mass-production of PCI-Express SSDs for data-centers that implement the latest-generation 3D QLC NAND flash memory. The new QLC (4 bits per cell) NAND flash memory enables 33% increases in densities over TLC NAND flash, and with 3D (stacks), the density per chip is further multiplied. Built in the 15 mm-thick 2.5-inch form-factor with U.2 interface, the drive is built for the rigors of "warm storage" (data that isn't hot, but isn't cold/archival, either). Such drives can be slower than "hot data" drives based on faster MLC or even SLC NAND flash, but almost always up; and faster than HDDs. The first 3D QLC NAND-based SSD, which probably uses the same chips as this drive, is the Micron 5210 ION, which was launched in May.