Crucial X8: External USB 3.2 Gen2 SSD uses QLC memory


Crucial has unveiled the X8, an external SSD with USB 3.2 Gen2 connectivity. There are only a few of them, including the Adata SE800 (test) and Sandisk's Extreme Pro Portable SSD. However, unlike its competitors, Crucial relies on four-bit (QLC) flash memory instead of three-bit (TLC) per cell.

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Inside the X8 is a M.2-2280 SSD, which resembles the Crucial P1, an NVMe / PCIe SSD. The Silicon Motion SM2263EN controller is retained, but with different firmware settings, and more at the same time. The SM2263EN uses a DRAM cache and supports four PCIe Gen3 lanes. It is connected to an ASM2362 from Asmedia, an NVMe / PCIe to USB 3.2 Gen2 bridge chip. The ASM2362 uses only two lanes for 2 GB / s, which is more than the theoretical 1.25 GB / s of USB 3.2 Gen2.

The Crucial X8's 3D flash memory is a so-called QLC from Micron, the parent company. This stands for Quad Level Cells or German for memory cells with four bits and thus 16 voltage states. As a result, QLC flash is comparatively slow to describe, the Crucial P1 creates just over 100 MB / s, and thus less than a hard drive. Therefore, in QLC, as in TLC, a so-called SLC pseudo buffer, that is, a write cache, is used. The Crucial P1 has a size of 5 GB (500 GB) and 12 GB (1 TB).

For the Crucial X8, however, the manufacturer has set the buffers to 100 GB (500 GB) and 200 GB (1 TB), which means that even large write processes should run quickly. Due to the USB 3.2 Gen2 connection, the sequential read rate of the Crucial X8 is up to 1,060 MB / s, the write rate is slightly lower. The manufacturer advertises it as an archive for game libraries, for 4K video projects, or as a console load time accelerator.

The Crucial X8 supports Apple's Time Machine and Microsoft's Windows File History Backup, plus it can be encrypted via File Vault or Bitlocker. The manufacturer calls $ 120 for the 500-gigabyte and $ 190 for 1-TB variant. Crucial gives a three-year warranty.