Enhanced SD 91 Specification to Accelerate SD Card Speeds

Despite advancements, SD cards remain relatively slow, which presents a significant challenge for technologies such as 8K video recording, handheld PC gaming, and other applications that require high data transfer speeds and reliable storage. To address this issue, the SD Association has introduced the new SD 9.1 specification, which doubles the data transfer rate compared to existing SD cards.

Previously, high-end SD cards were limited to speeds of 985 MBps or less using PCIe Gen3 connectivity. However, the new SD 9.1 specification incorporates PCIe Gen4 connectivity, enabling a maximum card speed of 1.9 GBps. This increased bandwidth is suitable for handling large 8K video files, video games, and other data-intensive media. Even for everyday file transfers, users will notice a significant improvement in speed when utilizing a PCIe Gen4 connection.

Increased speed results in increased heat, which requires SD cards to be throttled in order to cool down. Throttling temporarily reduces transfer speed, which can interrupt active recordings or file transfers. To maintain continuous speeds and prevent throttling, the SD 9.1 specification includes new power management thresholds and thermal performance upgrades. Additionally, host devices like cameras or game consoles can now control the internal temperature of an SD card.

Intriguingly, SD 9.1 also enhances the reliability of multi-stream recording. While the specifics may be perplexing, the underlying concept is that SD 9.1 can more effectively handle simultaneous recordings from multiple cameras or other sources. For more detailed information on this particular topic, refer to the SD 9.1 white paper.

With the release of SD 9.1, the SD Association is introducing four new speed classes for existing SD Express card formats. These speed classes, namely SD Express Speed Class 150, Speed Class 300, Speed Class 450, and Speed Class 600, simplify the process of identifying and purchasing an SD card. Each speed class is indicated by a number that represents the transfer speed in megabytes per second, along with a pill-shaped icon featuring the letter "E" and the corresponding speed class numeral imprinted on the cards.

Please be aware that there is no specified launch date for the new SD 9.1 specification. It is important to note that in order to take advantage of the speed, thermal, and power enhancements, a host device must support the SD 9.1 specification. For further details, refer to the SD 9.1 white paper or visit the SD Association's blog.

Source: SD Association via PC World

Editor's P/S

**Paragraph 1**

The new SD 9.1 specification is a significant upgrade over the previous SD 9.0 specification. The most notable improvement is the doubling of the maximum data transfer rate from 985 MBps to 1.9 GBps. This increase in speed is made possible by the adoption of PCIe Gen4 connectivity. The SD 9.1 specification also includes new power management thresholds and thermal performance upgrades to prevent throttling. Additionally, host devices like cameras or game consoles can now control the internal temperature of an SD card.

**Paragraph 2**

The SD 9.1 specification also introduces four new speed classes for existing SD Express card formats. These speed classes, namely SD Express Speed Class 150, Speed Class 300, Speed Class 450, and Speed Class 600, simplify the process of identifying and purchasing an SD card. Each speed class is indicated by a number that represents the transfer speed in megabytes per second, along with a pill-shaped icon featuring the letter "E" and the corresponding speed class numeral imprinted on the cards.

Overall, the SD 9.1 specification is a major upgrade that will benefit users who need fast and reliable storage for their devices.