SD Express

The SD Association, which oversees the design of SD cards, on Tuesday, announced the SD 8.0 Specification for SD Express memory cards, which boasts of insane transfer speeds. 

Based on the latest NVMe specification (up to version 1.4), these SD 8.0 cards can deliver a maximum data transfer rate of nearly 4 gigabytes per second (GB/s) or 3,940 Mbps with PCI Express (PCIe) 4.0 architecture.

They are also backwards-compatible with old card readers that use previous specifications.

“By dramatically increasing the speeds for SD Express we’re giving device manufacturers and system developers more storage choices,” said SD Association President Hiroyuki Sakamoto. “SD 8.0 may open even more opportunities for extra high-performance solutions using removable memory cards. 

“PCI-SIG® is pleased to see that SDA is continuing to adopt even faster PCIe technology configurations using PCIe 4.0 interface and dual lanes for one of the top leading removable memory cards – SD,” said Al Yanes, PCI-SIG President, And Chairman. 

“PCIe specification conformance tests are available today by major test vendors, offering a significant advantage for any new PCIe technology adopter.”

The new specification provides two faster transfer rate options for SD Express memory card by supporting either PCIe 3.0 x2 or PCIe 4.0 x1 architectures with up to ~2GB/s and with PCIe 4.0 x2 technology with up to 4GB/s.

“SD Express cards offering PCIe 4.0 x1 architecture use the same form factor as defined for SD 7.0 specification cards with a second row of pins to deliver transfer speeds up to 2 GB/s. SD Express cards supporting dual PCIe lanes (PCIe 3.0 x2 or PCIe 4.0 x2 technologies) have three rows of pins,” says The SD Association.

Further, SD Express gigabyte speeds bring new storage opportunities for devices with demanding performance levels, across a variety of industries. 

According to the SD Association, the cards can move large amounts of data generated by data-intense wireless or wired communication, super-slow motion video, RAW continuous burst mode and 8K video capture and playback, 360-degree cameras/videos, speed-hungry applications running on cards and mobile computing devices, ever-evolving gaming systems, multi-channel IoT devices and automotive to name a few. 

The SDA makes adoption of SD Express easy allowing companies to use existing test equipment and saving in product development costs. The SD 8.0 specification continues giving system developers access to PCIe and NVMe technologies, such as Bus Mastering, Multi Queue (without locking mechanism) and Host Memory Buffer.

The SD Association has confirmed that SD Express will be offered on SDHC, SDXC and SDUC memory cards, which means it could soon be on a 128GB SDUC card but we shall have to wait and see. Having said that, it may take a while for us to see SD Express cards with SD 8.0 specification in action.

To know more about the new memory card specifications, you can read the whitepaper released by the association.