Samsung PM991a 512GB PCI-Express 3.0 x4 NVMe M.2 2242 Solid State Drive (SSD) – MZ-ALQ512B

Samsung PM991a 512GB NVMe PCIe 3.0 M.2 2242 OEM SSD

The Samsung PM991a MZ-ALQ512B is a compact M.2 2242 NVMe PCIe 3.0 x4 SSD designed for ultra-thin laptops, compact embedded systems, and OEM platforms requiring high-performance storage in a shorter 42mm form factor not commonly available in consumer SSD lines.

Key Features

• 512GB NVMe PCIe 3.0 x4 in the compact M.2 2242 (42mm) form factor
• Samsung TLC V-NAND for balanced performance, endurance, and reliability
• Sequential read up to 3,100 MB/s for fast OS boot and application loading
• OEM-grade Samsung PM991a controller with enterprise-influenced power management
• Low-profile 2242 length for ultra-compact laptops and embedded OEM platforms

Product Specifications

• Part Number: MZ-ALQ512B
• Manufacturer: Samsung
• Capacity: 512GB
• Interface: NVMe PCIe 3.0 x4
• Form Factor: M.2 2242 (22mm x 42mm)
• NAND Type: Samsung TLC V-NAND
• Key: M-Key

Storage Specifications

• Sequential Read: Up to 3,100 MB/s
• Sequential Write: Up to 1,700 MB/s
• Random Read (4K): Up to 350,000 IOPS
• Random Write (4K): Up to 300,000 IOPS
• Endurance (TBW): 300 TBW
• DRAM Cache: No (HMB — Host Memory Buffer)

Performance Specifications

• MTBF: 1,500,000 hours
• Operating Power: ~3.5W (active)
• Idle Power: ~0.05W (PS4 low power state)
• Operating Temperature: 0°C to 70°C
• Shock Resistance: 1,500G / 0.5ms

Use Cases

• Ultra-thin laptop storage upgrade requiring the shorter 2242 M.2 form factor
• OEM embedded system storage for industrial and compact computing platforms
• Secondary NVMe SSD in systems with a dedicated 2242 M.2 slot
• Storage upgrade for devices with 2242 slots (e.g., select Dell, Lenovo, and Microsoft Surface models)

Compatibility

• Compatible with M.2 2242 PCIe 3.0 x4 NVMe slots (M-Key)
• Not compatible with M.2 2280 (80mm) slots without a physical adapter bracket
• Supported by Windows 10/11, Linux, and ChromeOS platforms with NVMe driver support
• Compatible with select Dell Latitude, Lenovo ThinkPad, and Microsoft Surface devices with 2242 M.2 slots

Frequently Asked Questions

What is the difference between M.2 2242 and M.2 2280?

The numbers indicate the physical dimensions — 2242 is 22mm wide x 42mm long, while 2280 is 22mm wide x 80mm long. Many laptops only support one length, so verifying your device”s M.2 slot length is critical before purchase.

Does the PM991a support PCIe Gen4?

No — the Samsung PM991a uses PCIe 3.0 x4 interface. For Gen4 NVMe performance, Samsung”s PM9A3 or consumer 980 Pro series support PCIe 4.0.

Is the PM991a an OEM-only drive?

Yes — the Samsung PM991a is an OEM drive typically found in systems from Dell, Lenovo, and other OEMs. It may not include retail packaging but offers Samsung”s proven reliability and performance.

The Samsung PM991a MZ-ALQ512B fills a critical gap in the NVMe market — delivering genuine PCIe 3.0 x4 performance in the compact 2242 form factor that ultra-thin laptops and embedded platforms demand, making it the go-to NVMe upgrade for devices where standard 2280 drives simply do not fit.