microSD Express uses PCIe and NVMe technology, delivering transfer speeds up to 985MB/s—much faster than older microSD cards. In contrast, UHS-I microSD cards peak at 104MB/s, and UHS-II cards reach 312MB/s.
A key physical difference is the number of pins:
- Standard microSD and UHS-I cards have 9 pins.
- UHS-II cards add a second row, increasing the total to 17 pins.
- microSD Express keeps the 9-pin layout (like UHS-I) for backward compatibility but adds a second row of extra pins to enable PCIe connectivity—resulting in a total of 17 pins.
This design allows microSD Express to fit and function in older slots (though only at legacy speeds), while unlocking blazing-fast PCIe/NVMe performance in compatible devices. Perfect for 4K/8K video, gaming, and mobile computing.
