Lexar NM790 4000GB

The Lexar NM790 4000GB represents the maturation of DRAM-less PCIe 4.0 architecture, utilizing the Maxio MAP1602A controller paired with YMTC’s 232-layer 3D TLC NAND. It leverages Host Memory Buffer (HMB) technology and the high I/O bandwidth of Xtacking 3.0 NAND to effectively saturate the PCIe 4.0 x4 interface. The 4TB model achieves this density on a single-sided PCB thanks to the extreme density of the NAND packages. Field analysis indicates the NM790 exhibits superior power efficiency compared to older high-end DRAM-equipped competitors based on the Phison E18 controller, resulting in lower operating temperatures under load. Its thermal profile and single-sided 2280 layout make it suitable for ultra-thin laptops and the PlayStation 5. The drive uses a large dynamic SLC cache for high burst speeds, with sustained write performance reverting to native TLC once that cache is saturated during massive, continuous transfers.

Key Specifications

• Interface: PCIe 4.0 x4, NVMe 1.4
• Max Sequential Speeds: 7400 MB/s Read, 6500 MB/s Write
• Controller: Maxio MAP1602A (4-channel)
• NAND Type: YMTC 232-Layer 3D TLC (Xtacking 3.0)
• DRAM Cache: No (Uses Host Memory Buffer ~40MB)
• Endurance: 3000 TBW
• Physical Characteristics: Single-sided M.2 2280 PCB

Hardware Alternatives

• Acer GM7000 4000GB: utilizes the same Maxio MAP1602 controller and 232-layer TLC NAND, with performance generally indistinguishable aside from firmware and binning differences
• Samsung 990 PRO 4000GB: direct competitor that uses a proprietary controller with on-board DRAM, offering better consistency in heavy random I/O workloads compared to HMB-reliant designs
• Western Digital WD_BLACK SN850X 4000GB: another high-throughput competitor with on-board DRAM and a proprietary controller, providing more consistent performance under sustained random I/O