The Toshiba BG4 is a solid-state drive in the M.2 2230 form factor, launched on January 8th, 2019. It is available in capacities ranging from 128 GB to 1 TB. This page reports specifications for the 256 GB variant. With the rest of the system, the Toshiba BG4 interfaces using a PCI-Express 3.0 x4 connection. The SSD controller is the KBG40ZNS from Toshiba, a DRAM cache is not available. Toshiba has installed 96-layer TLC NAND flash on the BG4, the flash chips are made by Toshiba. To improve write speeds, a pseudo-SLC cache is used, so bursts of incoming writes are handled more quickly. The BG4 is rated for sequential read speeds of up to 2,200 MB/s and 1,400 MB/s write; random IO reaches 330K IOPS for read and 190K for writes.
The SSD's price at launch is unknown. The warranty length is set to five years, which is an excellent warranty period. The TBW rating for the Toshiba BG4 256 GB is unknown, too.