Solid-State Drives store data purely electronically via NAND flash memory chips managed by an onboarding controller circuit. They contain no moving mechanical components.
┌────────────────────────────────────────────────────────┐
│ SSD Architecture │
│ ┌────────────┐ ┌────────────┐ ┌────────────┐ │
│ │ Controller │ │ NAND Flash │ │ NAND Flash │ │
│ └────────────┘ └────────────┘ └────────────┘ │
│ (Brain) (Memory Chip) (Memory Chip) │
└────────────────────────────────────────────────────────┘
Physical Dimensions & Form Factors
- 2.5-Inch Standard: Uses the identical physical footprint as a laptop HDD (69.85 mm × 100 mm × 7 mm), making them directly swappable via standard SATA or SAS cables.
- M.2 (Formerly NGFF): A slim, card-like form factor that slots flat against the motherboard. Width is standard at 22 mm, while lengths dictate the module designation:
- M.2 2230: 22 mm × 30 mm (Commonly found in Steam Decks and Microsoft Surface tablets).
- M.2 2242: 22 mm × 42 mm.
- M.2 2280: 22 mm × 80 mm (The standard for modern commercial consumer desktops and laptops).
- M.2 22110: 22 mm × 110 mm (Enterprise-grade drives featuring power-loss protection capacitors).
- U.2 / U.3 (SFF-8639): High-performance 2.5-inch enterprise form factor thicker than commercial consumer drives (15 mm), built to handle heavy thermal dissipation.
- Add-in Card (AIC / PCIe Expansion Slot): A full-sized desktop expansion card interface designed to plug directly into open PCIe slots on a motherboard.
Logical Protocols vs. Connection Interfaces
A common point of confusion is separating the data highway (Interface) from the communication language (Protocol).
- SATA Protocol: Restricted to a maximum architecture ceiling of roughly 550–600 MB/s. It can utilize a standard 2.5" housing or an M.2 slot (B+M Key).
- NVMe Protocol (Non-Volatile Memory Express): Designed explicitly for lightning-fast flash storage leveraging high-bandwidth PCIe lanes. NVMe drives utilize M.2 (M Key), U.2, U.3, or AIC physical connections.
- PCIe (Peripheral Component Interconnect Express) Generations:
- PCIe 3.0: Transfers up to ~3,500 MB/s.
- PCIe 4.0: Transfers up to ~7,500 MB/s.
- PCIe 5.0: Exceeds 10,000+ MB/s sequential read rates.