Samsung 990 Pro - M.2 PCIe Gen4 NVMe SSD - 4TB

The Samsung 990 Pro is Samsung's premium Gen4 NVMe drive, pairing Samsung's Pascal controller with V-NAND 3-bit MLC (TLC) and a dedicated LPDDR4 DRAM cache. Sequential read/write speeds of 7,450/6,900 MB/s push close to the theoretical ceiling of the PCIe 4.0 x4 interface. This is the Gen4 drive to beat.

DRAM Makes the Difference

The 990 Pro's DRAM cache (1GB per 1TB of flash, so 4GB on the 4TB model) keeps the flash translation layer in fast memory at all times. This shows up in two ways: QD1 random performance stays responsive (22K/80K IOPS), and sustained mixed workloads don't hit the performance cliffs that HMB drives experience when the host memory buffer gets evicted. For desktop use as a primary OS and application drive, this consistency is the 990 Pro's main advantage over DRAMless alternatives.

Random I/O

Random performance scales with capacity: 1,200K/1,550K IOPS (1TB), 1,400K/1,550K IOPS (2TB), 1,600K/1,550K IOPS (4TB) at QD32. The 4TB model's read IOPS are the highest in the lineup. AES 256-bit hardware encryption (TCG/Opal) is included.

Endurance

600 TBW (1TB), 1,200 TBW (2TB), 2,400 TBW (4TB). Five-year warranty. Samsung Magician for health monitoring, firmware updates, and performance optimization.

Best for: The gold standard for Gen4. Primary desktop boot/application drives, workstations handling mixed I/O, and anyone who wants guaranteed consistent performance under load. PS5 compatible (heatsink recommended).

Avoid if: Your workload is purely sequential (large file transfers) and you have a Gen5 platform. A Gen5 drive like the T700 or 9100 PRO will outperform in raw throughput. For budget builds, the 990 EVO Plus gets close to these speeds without DRAM at a lower price.