Sony 64 GB MicroSDXC Card: Speed Failure Redux

After about 1 TB of data spread over three months and maybe 100 bike rides, the second Sony SR-64UY 64 GB MicroSDXC card I bought last summer has failed… barely two weeks inside the one year warranty.

As with the first card, this one works fine except for the speed: it cannot record at 1920x1080p @ 60 fps. The only indication comes from aiming another camera at the display to capture the failure as it happens.

Just before the failure:

HDR-AS30V - MicroSDXC failure - 1
HDR-AS30V – MicroSDXC failure – 1

It’s taking stock of the situation:

HDR-AS30V - MicroSDXC failure - 2
HDR-AS30V – MicroSDXC failure – 2

Presumably, it’s patching up the abruptly terminated file:

HDR-AS30V - MicroSDXC failure - 3
HDR-AS30V – MicroSDXC failure – 3

Another box is on its way to Sony Media Services…

Over the last year, the price of an almost certainly genuine Sony SR-64UY Class 10 UHS-1 MicroSDXC card has dropped by 2.2 dB: $40 to $24. Now, however, the SR-64UY is the “old model”, so you can pay $30 (-1.3 dB) for an SR-64UY2 rated at 70 MB/s transfer speed (up from 40 MB/s), albeit with no change in the card’s speed class.


Both cards failed after writing 1 TB of data (give or take maybe 20%) in 4 GB chunks over the course of 100 recording sessions. The cards still work, in the sense that they can store and accurately retrieve data, just not at the Class 4 (not Class 10) speed rating required by the HDR-AS30V at 1920x1080p @ 60 fps.

The table in the Wikipedia Secure Digital article says Class 4 = 4 MB/s, which is slightly faster than the camera produces 4 GB files in 22:43 min:sec = 3 MB/s. A Class 10 card should write at a sustained 10 MB/s, so the SR-64UY write speed has dropped by at least a factor of 3 from the spec. I’d expect the root problem to be the error correction / block remapping / spare pool handling time has grown as the number of failed blocks eats into the card’s overcapacity, but I have no inside information.

When the replacements slow down, I’ll see how they work as Raspberry Pi memory…

8 thoughts on “Sony 64 GB MicroSDXC Card: Speed Failure Redux

    1. Basically, I bought two Sony cards, stuck one in the camera, used it until it failed, and now I’m using the second one, with the first replacement waiting its turn. I extract the video files through the USB port to avoid fat-fingering the MicroSD card back into its slot.

      It’ll be interesting to see how long the Kingston 8 GB Class 10 / U1 card that came with the Fly6 survives under the same exercise regimen.

      Which is a long way of saying I don’t have any comparative results with other cards under the same conditions.

      If I weren’t so fixated on capturing video at the camera’s maximum resolution and highest speed, the Sony cards would still work, but that’s definitely cold comfort.

  1. Interestingly, it turns out that ‘Class x’ doesn’t actually guarantee X-mbps write performance except when the card is empty! See p.84-85 of this doc (labelled as p96-97 in the pdf):

    Click to access part1_301.pdf

    1. I didn’t know that, but, somehow, I’m not surprised that the “speed rating” doesn’t really mean very much. Given that I copy-and-delete the AS30V files after every ride, the card always starts nearly empty, never gets more than maybe 1/4 full, and still fails after just a few minutes from a cold start.

      In contrast, Cycliq recommends never deleting any files and letting the Fly6 manage the FAT filesystem: it discards a 500-ish MB file whenever it needs more space, so the card always runs nearly full. On the other paw, the Fly6 writes data at 500 MB/10 min = 0.83 MB/s, so it should work with nearly any card, even though they specify Class 10.

      Thanks for the pointer!

    2. That is interesting. I have a camera that can shoot 1200fps flat out, and the instructions for it insist in a “class 10” card, which was a bit of a rare bird when the camera first came out. Seems to work okay, however.

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