SD Bus Interfaces vs. xD-Picture Card
Comparing 2 standards across 13 specifications. 13 key differences identified.
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).
xD-Picture Card ('eXtreme Digital') is a proprietary flash memory card format developed by Olympus and Fujifilm in 2002 (manufactured by Toshiba and Samsung). Measuring 20.0 × 25.0 × 1.7 mm with 18 surface pads, it utilized a controllerless architecture where the host camera directly managed the raw NAND flash silicon, before being discontinued in 2010 in favor of SDHC.
Specification Comparison Table
13 Parameters| Parameter / Spec | ||
|---|---|---|
|
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 Manufacturers
|
— | Olympus Corporation & Fujifilm (manufactured by Toshiba/Samsung) |
|
Introduction Year
|
— | 2002 (superseded SmartMedia) |
|
Physical Dimensions
|
— | 20.0 mm × 25.0 mm × 1.7 mm (Weight: ~2.8 g) |
|
Pad Configuration
|
— | 18 gold-plated contact pads (bottom surface) |
|
Controller Architecture
|
— | Controllerless (Host camera CPU directly controls raw NAND flash) |
|
Variants & Capacities
|
— | Standard (16–512MB SLC), Type M (256MB–2GB MLC), Type H (256MB–2GB High Speed), Type M+ (up to 2GB) |
|
Nominal Operating Voltage
|
— | 3.3V nominal |