The WD_BLACK SN850 comes in a small, black box. Along with a picture of the drive, the front advertises a few of its key features including its 1TB capacity, Gen4 interface and maximum read speed. The back of the box also has a small window that lets you see the drive and view the model name and serial number.


Physical Features:

The WD_BLACK SN850 uses the 2280 form factor for M.2 (NGFF) SSDs. It measures 22 x 80 x 2.38 mm and tips the scales at a mere 7.5g. The drive also has an "M key" edge connector which provides PCIe SSDs with up to 4x lanes of bandwidth.

The WD_BLACK SN850 uses Western Digital's new G2 (20-82-10034-A1) controller. Not much is known about this controller aside from that it delivers improved low queue-depth performance over its predecessor as well as faster file transfers thanks in part to a new cache technology.

For the 1TB version of the WD_BLACK SN850, Western Digital has opted to use its own 96-layer 3D TLC NAND flash. Looking at the picture above, you can see that there are two 512GB NAND flash packages on the top of the PCB. The drive also has a single 1GB DDR4 SDRAM memory chip that is used for caching.