16GB UHS-1 SDHC cards bogging down after 5000 photos written on Nikon V1

I recently purchased a couple of new SDSDRX3-016G-A21 Sandisk 16GB cards, that I’m using on my Nikon V1. These are the 45 MB/sec “Extreme” rated UHS-1 SDHC cards. Serial numbers are BL1231321759D and BL1229321759D.

I have an application where I take a photo every 2 seconds (Medium/Fine jpg), triggered via automated infrared remote. Everything starts off fine with this model card installed, but after 5000 photos have been taken, writes start to bog down. On a freshly formatted and empty card, it takes a fraction of a second to write the ~700k file when the photo is taken. But when the slowdown occurs, this stretches out to approximately 3 seconds to write the same file, and sometimes as long as 5 to 8 seconds. Thus in my application I’m missing frames when this occurs, since I’m firing the IR remote every 2 seconds, but the camera and card take longer to write a photo than that.

Curiously, when I use an old Sandisk Class 2 8GB card, everything works fine. No slowdowns occur, even to the point of filling the card with 10,000 photos.

I’ve tried using SDFormatter on my Win7 PC to fully format the cards in case the file system is being fragmented in some way, but it doesn’t seem to make any difference. Neither does doing ‘full’ formats in the camera. I’ve tried both exFAT and FAT32 file systems – no difference.

When a card goes into this slow state, it remains unreliable until I reformat it. When I put the card back in my PC in this bogged down state, and try writing 600KB image files to it, THE WRITES ARE JUST AS SLOW ON THE PC AS ON THE CAMERA. Copying 50 of these files to the card took over a minute, writing (per Windows Explorer) at an average of only 220KB per second! Doing the same copy on one of these cards, empty and freshly formatted and not in a ‘bogged-down’ state, the 50 file copy happens virtually instantaneously - so fast I don’t even have time to click in the copy window to display what the transfer rate is.

An additional note: one time I kept adding files to the bogged down card on the PC, and after a few hundred more writes, it seemed to return to normal. I put it back in the camera, and writes seemed normal and fast at first, but after another couple hundred shots it began to bog down again.

And one more: I tried this writing various file sizes (from 700k to 2MB), and the bog down always occurred at the 5000 file mark. So the problem appears to be related to the number of files written, not the number of gigabytes written.

I bought these more expensive cards because they are on Sandisk’s supported list for Nikon V1, and because I need consistent speed from them. I am not receiving anything near that, and as such they are useless for my application.

I believe they have a design or production flaw, as both cards (from different batches) exhibit exactly the same ‘bog-down’ problem, at exactly the same point. I’ve submitted this info in an RMA request with Sandisk, so we’ll see how it goes.

Has anyone else run into this kind of problem? I realize most folks probably don’t put 5000 photos on a card before downloading a batch and wiping the card, so most will never experience it… Also, most folk’s file sizes are probably much larger and they can’t fit 5000 pics on a 16GB card anyway. So I may be the only ‘beta tester’ that has gotten to the 5K photo mark on one of these 16GB cards!


I have never seen any issue like this with any of my cards. I do have a few of the exact same one you are referring to. That said I also never have 5000 files on a card. You are probably best off dealing with sandisk support on this one as it seems to be a pretty rare scenario.

I RMA’d these two cards to Sandisk on May 22. UPS shows they got them on 5/30. Nearly two weeks later, and “My SanDisk” shows no progress - not even that they’ve received them. Does it usually take this long to process an RMA?