{"id":3412,"date":"2020-05-22T14:00:00","date_gmt":"2020-05-22T14:00:00","guid":{"rendered":"https:\/\/aviancetechnologies.com\/blog\/blog\/sd-express-will-support-pcie-4-0-but-dont-hold-your-breath\/"},"modified":"2020-05-22T14:00:00","modified_gmt":"2020-05-22T14:00:00","slug":"sd-express-will-support-pcie-4-0-but-dont-hold-your-breath","status":"publish","type":"post","link":"https:\/\/aviancetechnologies.com\/blog\/sd-express-will-support-pcie-4-0-but-dont-hold-your-breath\/","title":{"rendered":"SD Express will support PCIe 4.0, but don’t hold your breath"},"content":{"rendered":"

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SD Express will support PCIe 4.0, but don’t hold your breath<\/h2>\n

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The race to be the world\u2019s next high-performance memory card standard took it up a notch this week when the SD Association said it will adopt PCIe 4.0 for SD Express cards.<\/p>\n

Yes, you heard that right: PCIe 4.0 in a postage stamp-sized memory card, a move that will make SD cards essentially on a par with some of the fastest memory card standards out right now.<\/p>\n

SD Express itself isn\u2019t new, as the SD Association introduced it with version 7.0 of the spec using PCIe 3.1. With the new 8.0 spec, the SD Association moves to using up to two lanes of PCIe 4.0 for up to 4GBps of throughput.<\/p>\n

\"expresscard\"<\/a> SD Association<\/small>
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An SD Express card that can support two lanes of PCIe 4.0 will feature an additional third row of pins.<\/p>\n<\/figcaption><\/figure>\n

SD Express looks similar to existing SD cards, but the underlying interface changes significantly with the adoption of PCIe and NVMe. The SD Association made the switch from its UHS bus to PCIe to ease adopting higher speeds in memory cards.<\/p>\n

SD Express cards maintain some backward compatibility. They will adopt both the PCIe 3.0 and 4.0 bus, as well as keep the very common UHS-I bus. That means when inserted into a camera, drone, or device that can support SD Express over PCIe, it\u2019ll run over PCIe. When installed in an older camera or card reader in a laptop, it will fall back to the UHS-I bus and offer up to 104MBps read and write speeds.<\/p>\n

\"sd<\/a> SD Association<\/small>
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The SD card’s strength and weakness is its heavy focus on the consumer market.<\/p>\n<\/figcaption><\/figure>\n

Which memory card standard will win?<\/h2>\n

With SD Express 8.0 out now, the field for high-performance memory cards gets far more interesting, but don\u2019t expect immediate change. The CompactFlash Association\u2019s CFexpress\u2014which also uses PCIe\u2014is clearly the preferred standard in high-end imaging gear.<\/p>\n

Sony\u2019s PCIe-based XQD 2.0 will largely be absorbed into CFexpress 2.0, as both are compatible. The older SATA-based CFast 2.0 is likely to fade away, along with cameras that still use older ATA-based CompactFlash.<\/p>\n

SD Express 8.0 will likely take years to be adopted, but its competitor probably won\u2019t be CFexpress 2.0. It\u2019ll be SD cards using the older UHS-II bus. We say that because even though the original SD Express has been out for a year now, we’ve seen scant adoption of it. For that matter, few cameras or devices even take advantage of UHS-III speeds, which\u00a0became available in 2017. CFexpress 2.0 Type B cards will be used in Canon\u2019s upcoming EOS 1DX Mk III, Nikon\u2019s D6 and Canon\u2019s EOS R5. The EOS R5 will have a second memory slot for SD cards, and Sony\u2019s A7R-IV will also use SD\u2014but both are using the slower UHS-II spec.<\/p>\n