image of Crucial X8 M.2 SSD

Crucial X8

SSD Specification and Info

Crucial X8 is an Entry-Level NVMe SSD produced and sold by Crucial. The device comes with USB 3.2 Gen 2x1 interface and M.2 form factor - a good fit for both desktop and laptop computers. This SSD has a maximum sequential read-write speed of up to 1050/1000 MB per second, making it ideal for gaming and workstation PCs.

Crucial X8 is equiped with DRAM memory, and a QLC NAND flash memory with 64 cell layers.


Specification

Model
InterfaceUSB 3.2 Gen 2x1
Form factorM.2
Capacity500GB-1TB
ControllerSMI SM2263
ConfigurationDual-core, 4-ch, 4-CE/ch
DRAMYes
HMBNo
NAND brandMicron
NAND typeQLC
Layer64
R/W speed1050/1000 MB/s
TierEntry-Level NVMe
ManualCrucial X8

NAND type

Crucial X8 is using a QLC (4 bits per cell) NAND manufacurted by Micron with 64 cell layers on top of each other.

QLC is slow and less durable compared to TLC and SLC. The TLC is the most common type of SSD NAND flash memory found on the market at the moment. It is faster, less durable, but still cheaper than the other, more expensive variants - SLC and MLC.

The Controller

Crucial X8 is using SMI SM2263 SSD controller to connect the NAND memory to the USB 3.2 Gen 2x1 interface. The controller has Dual-core, 4-ch, 4-CE/ch configuration.

Typically, SSD controllers are microprocessors. In this case we have Dual-core, 4-ch, 4-CE/ch processor responsible for controlling the SSD in such way, so that the data coming from the interface can be stored on to the NAND flash memory.

Some SSDs have simpler controllers with fewer communication channels and less cores.

Among other things, the controller also manages the SLC caching, optimizing the DRAM cache, encryption, LDPC, garbage collection, wear-leveling as well as TRIM

DRAM Cache

Crucial X8 has a separate DRAM chip to store the SD mapping tables. DRAM cache speeds up the data access significantly compared to the DRAM-less models.

As soon as the OS requests some data from the SSD, the SSD needs to know exactly where it is on the drive. Because garbage collection moves the data constantly, the controller relies on the mapping tables to locate it.

These tables are stored in DRAM cache, where they are accessed much more quickly than in NAND flash.

Therefore, SSDs with DRAM-less architecture have more random write and read operations. This makes the device perform worse and last shorter if they are not HMB enabled.

HMB Support

There is no HMB architecture available on the Crucial X8 to store the mapping tables. The device either doesn't support the architecture or uses DRAM cache.

The HBM is used to reduce the cost of production of NVMe SSDs with DRAM Cache, SSDs with this type of controllers can leverages the host system's DRAM instead of an onboard DRAM chip to host the FTL mapping table used by flash storage.