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…
The Smell of Molten Projects in the Morning 
wow what brands do you recommend? I been using sandisk so far by eyeing a Sony or Samsung
Still haven’t a clue, but I’m thinking of comparing a (highly recommended) Sandisk Extreme Pro with some of Amazon’s cheap no-name offerings. There’s certainly a difference, but I don’t know which way the cost-performance ratio will go.
One guy in the local LUG buys the cheapest possible MicroSD cards for his Android development projects, uses one until it dies, then chucks up the next one. Of course, he follows the “If you only have one copy, you have zero copies” principle of data storage…
This might be timely to note: chaosmanorreviews dot com is doing a 3 part series on a RAID 6 array for Jerry Pournelle. Looks like they’ll be using 4 4TB drives (16 TB worth) to get 8 TB worth of relatively bulletproof storage. The series started 9/21/2015. I’m not willing to go that route, but I should start putting extra copies of my own data on nonmagnetic media. A few decades worth of slides would be a huge pain to recreate.
I recently read the advice that you should never, ever, use identical drives for a RAID array, because they tend to have common-mode failures. That said, I’ve never seen anybody use dissimilar drives…
I have been seriously hit when a bad power supply knocked out four drives in one shot. Also, vendors are starting to warn that a 2TB drive can take days to regenerate after a failure, so 4TB drives will be worse.
thanks. I picked up 2 Sandisk Extreme Pro 32 (Shimano cam) and 64 (older Garmin Virb Elite) gb cards over the past few months while on sale and had a gift card to cut down the cost. so far so good. but I figured I ask someone who uses microSD cards like a boss!
I got a PNY (I believe) microsd the other day because it’s all that best buy had in stock.
It lasted through one write cycle: I wrote a beaglebone image to it, verified it, pulled it out of the card reader, and from that moment onwards nothing has even recognized it when I plug it in. It’s like it isn’t even there.
Sigh.
Well, that puts a lower bound on the lifetime…
Somewhere I saw a chart correlating retail “brands” with actual manufacturers. IIRC, there were maybe six factories supplying dozens of brands; surely, you can get any slice of the output quality distribution you can afford.
[Edit: I misremembered Bunnie’s writeup of his experiences with fake MicroSD cards.]
Yeah, at least it was actually 8GB, albeit with an MTBF of thirty minutes.