# item.guide
Side-by-Side Comparison Memory Cards

SD Bus Interfaces vs. SD Card

Comparing 2 standards across 13 specifications. 13 key differences identified.

Comparing:
SD Bus Interfaces
SD Card
SD Bus Interfaces →

SD Bus Interfaces define the physical and electrical signaling architectures through which SD and microSD cards transfer data with host controllers. Spanning legacy Default/High Speed, Ultra High Speed tiers (UHS-I up to 104 MB/s, UHS-II up to 312 MB/s, UHS-III up to 624 MB/s), and PCIe/NVMe-based SD Express (up to 3,940 MB/s).

View full SD Bus Interfaces spec sheet →
SD Card →

The SD Card (Secure Digital) is the global standard removable flash memory form factor established in 1999 by Panasonic, SanDisk, and Toshiba (SD Association). Measuring 32.0 × 24.0 × 2.1 mm, it spans capacity generations from original SDSC (up to 2GB) and SDHC (up to 32GB) to SDXC (up to 2TB) and SDUC (up to 128TB).

View full SD Card spec sheet →

Specification Comparison Table

13 Parameters
Parameter / Spec
SD Bus Interfaces
SD Card
Default Speed (DS) / High Speed (HS)
12.5 MB/s (25 MHz @ 3.3V) / 25 MB/s (50 MHz @ 3.3V) —
UHS-I (SD 3.01)
SDR12 (12.5 MB/s), SDR25 (25 MB/s), SDR50 (50 MB/s), DDR50 (50 MB/s), SDR104 (104 MB/s @ 208 MHz 1.8V) —
UHS-II (SD 4.0)
156 MB/s (Full Duplex) / 312 MB/s (Half Duplex) via 2nd pin row LVDS (0.26V) —
UHS-III (SD 6.0)
312 MB/s (Full Duplex) / 624 MB/s (Full Duplex dual-lane LVDS) —
SD Express (SD 7.0 / 8.0)
985 MB/s (PCIe 3.0 x1), 1970 MB/s (PCIe 4.0 x1 / 3.0 x2), up to 3940 MB/s (PCIe 4.0 x2) —
SD Express Protocol Stack
PCI Express (PCIe) + NVM Express (NVMe v1.3/1.4) over SD pins —
Governing Body
— SD Association (SDA)
Physical Dimensions
— 32.0 mm × 24.0 mm × 2.1 mm
Pin Configurations
— 9 pins (UHS-I / Legacy) / 17 pins (UHS-II / UHS-III dual-row) / 19 pins (SD Express)
Capacity Standards
— SDSC (≤2GB), SDHC (4–32GB), SDXC (64GB–2TB), SDUC (2TB–128TB)
Standard File Systems
— FAT12/16 (SDSC), FAT32 (SDHC), exFAT (SDXC / SDUC)
Operating Voltages
— 2.7V–3.6V (Standard) / 1.8V (UHS-I/II signal voltage)
Mechanical Features
— Write-Protect slide notch (left edge), 45-degree polarized corner keying

Other Alternatives to Compare

Compare SD Bus Interfaces vs. CFast → Compare SD Bus Interfaces vs. CFexpress → Compare SD Bus Interfaces vs. CompactFlash → Compare SD Bus Interfaces vs. microSD → Compare SD Bus Interfaces vs. MultiMediaCard (MMC) → Compare SD Bus Interfaces vs. SD Speed Classes → Compare SD Bus Interfaces vs. Sony Memory Stick → Compare SD Bus Interfaces vs. xD-Picture Card →