A little over a year ago, I bought two Sony 64 GB MicroSDXC cards (let’s call them A and B). Both cards failed after less than six months in service and were replaced under warranty with Cards C and D:
The top card (C) is the most recent failure, the bottom (D) is the as-yet-unused replacement for Card D. Note that the difference: SR-64UY vs. SR-64UX, the latter sporting a U3 speed rating.
Note that the failure involves the card’s recording speed, not its read-write ability or overall capacity. Card C still has its nominal 64 GB capacity and will store-and-replay data just fine, but it can’t write data at the 25 Mb/s rate required by the camera… which is barely a third of the card’s speed rating. Also note that the writing speed is always a minute fraction of the reading speed that you see on the card.
I use these in a Sony HDR-AS30V action camera on my bike, so it’s pure Sony all the way. Although I don’t keep track of every trip, I do have a pretty good idea of what happened…
In service: about 2015-07-10
Failed to record 1920×1080 @ 60 f/s video: 2015-09-22
In round numbers, that’s 70 days of regular use.
My NAS drive has room for about a month of video, depriving me of a complete record of how much data it absorbed, but from 2015-08-21 through 2015-09-22 there’s 425 GB from 25 trips in 30 days. Figuring the same intensity during the complete 70 days, it’s recorded 800 to 900 GB of data (including my verification test). With 60 GB available after formatting, that amounts to filling the card 14 times.
That’s reasonably close to the 1 TB of data I’d been estimating for the failures of Cards A and B, so these Sony cards reliably fail their speed rating after recording 750 GB, more or less, of data.
We’ll see if they replace the replacement…