The SD Association reveal SD Express to deliver 985 MB/s transfer speeds
The SD Association reveal SD Express to deliver 985 MB/s transfer speeds
With SD 7.0, the maximum capacity of SD cards has increased from 2TB on SDXC to 128TB with SDUC, offering forward-looking support for ultra-high capacity applications. Note that SDUC cards can support SD Express if the card in question features the new EX modifier, making both standards inter-compatible and available separately.Â
What changes with SD Express is that the second row of pins from UHS-II cards is repurposed to support PCIe 3.0 x1 connections, with the new standard utilising the NVMe protocol to offer transfer speeds of up to 985MB/s. This change will allow future SD cards to provide transfer speeds that surpass SATA Solid State Drives, which is an amazing feat given the small form factor of SD cards.Â
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Support for NMVe 1.3 also adds several SSD-like specifications to the SD Express standard, like bus mastering, multi-queue, host memory buffer and several other enhancements while maintaining backwards compatibility with SD UHS104 and lower standards.Â
Because of the SD Associations repurposing of UHS-II pins with SD Express, the standard is not backwards compatible with either UHS-II or UHS-III speeds, preventing UHS-II/III cards from accessing their full speeds on SD Express hosts and SD Express cards from saturating UHS-II/III hosts, reverting to UHS104 speeds. Â
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While transfer speeds of 985MB/s seem excessive for an SD card, it is encouraging to see compact storage solutions offer more SSD-like features and increased transfer speeds, especially in an era where 8K video recording is becoming more popular and high-resolution/framerate video is becoming recordable on today’s smartphones.Â
This new standard will provide additional competition in the high-end video production market, though SD Express will also be usable for future mobile computing platforms, games consoles, automotive applications and a wide range of other applications.Â
You can join the discussion on the SD Association’s SD Express standard and its 985MB/s transfer speeds on the OC3D Forums.Â