# Restoring flash card write speed **URL:** \ **Category:** Contributing and equipment\ **Created:** [March 28, 2016, 2:37pm UTC](https://forum.mapillary.com/t/restoring-flash-card-write-speed/416 "2016-03-28T14:37:45Z")\ **Posts on this page:** 3\ **Page:** 1
**Author:** ![tryl](https://sea1.discourse-cdn.com/flex015/user_avatar/forum.mapillary.com/tryl/32/62_2.png) [@tryl](https://forum.mapillary.com/u/tryl)\ **Post date:** [March 28, 2016, 2:37pm UTC](https://forum.mapillary.com/t/restoring-flash-card-write-speed/416/1 "2016-03-28T14:37:45Z")
I just realized, that one of my flash cards has a very varying write speed. Some times 6-8 MB/s (which is not impressive for a SanDisk Class 10 that should write with at least 10 MB/s [Speed Class | SD Association](https://www.sdcard.org/developers/overview/speed_class/) ) but I have seen it down to 600 KB/s. **Update:** I have written a post about my experience and research on [microSD cards - don't buy to cheap](http://forum.mapillary.com/t/microsd-cards-dont-buy-to-cheap/430) . I read on [http://www.thriveforums.org/forum/toshiba-thrive-general-discussions/15040-sd-card-issues-problems-solutions.html](http://www.thriveforums.org/forum/toshiba-thrive-general-discussions/15040-sd-card-issues-problems-solutions.html) that it might be due to file system fragmentation and a normal formatting helped. It did not. Now I got the around 600 MB/s some times, where the lowest speed before was 1.3 MB/s. Has anyone knowledge in this area? The card is around 6 months old and have taken around 150.000 images + a little video which for the 64 GB card sums to around 15 total overwrites. Should I try to RMA it? Two of my other cards are still useable but only lets me write with 4 MB/S. Same type of card, same use but no video. PS. My card reader is a Lexar, that reads with up to 80 MB/s from these cards and should do more for faster cards. ---
**Author:** ![Harry](https://sea1.discourse-cdn.com/flex015/user_avatar/forum.mapillary.com/harry/32/82_2.png) [@Harry](https://forum.mapillary.com/u/Harry)\ **Post date:** [March 29, 2016, 10:54am UTC](https://forum.mapillary.com/t/restoring-flash-card-write-speed/416/2 "2016-03-29T10:54:13Z")
Could this problem also be the reason for your problem with shooting att 2 images per second? > [@Wrong: Xiaomi Yi doing 1 pic/0.5 without hacks](http://forum.mapillary.com/t/xiaomi-yi-doing-1-pic-0-5-without-hacks/415/2): > > Update: I set 1 camera to do 1/s at 12 mega pixels and another to do 2/s (an image every 0.5s) at 8 mega pixels. No issues at 1 sec at 12 mp. I did not find a gap where I looked. The camera filled the card. At 2/s at 8mp I saw the same as before: The camera skips a lot of pictures, probably because it is too slow. The camera filled the card - no crash. I use very fast Sandisk cards. They are not the issue. Afterwards I set a camera to 2 pic/sec (an image every 0.5s) and 5 mega pixels, which i… ---
**Author:** ![tryl](https://sea1.discourse-cdn.com/flex015/user_avatar/forum.mapillary.com/tryl/32/62_2.png) [@tryl](https://forum.mapillary.com/u/tryl)\ **Post date:** [March 29, 2016, 1:36pm UTC](https://forum.mapillary.com/t/restoring-flash-card-write-speed/416/3 "2016-03-29T13:36:28Z")
Definitely a possibility. In that test I used that card that at least got 4 MB/s and not the real bad one. I am currenty looking into the trim system command ( [Increase Performance and lifespan of SSDs & SD Cards](http://haydenjames.io/increase-performance-lifespan-ssds-sd-cards/) ) which is called ERASE for SD cards. But it does not seem like this card supports any of them: sudo hdparm -I /dev/sdd /dev/sdd: SG\_IO: bad/missing sense data, sb: 70 00 05 00 00 00 00 0a 00 00 00 00 20 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ATA device, with non-removable media Standards: Likely used: 1 Configuration: Logical max current cylinders 0 0 heads 0 0 sectors/track 0 0 – Logical/Physical Sector size: 512 bytes device size with M = 1024_1024: 0 MBytes device size with M = 1000_1000: 0 MBytes cache/buffer size = unknown Capabilities: IORDY not likely Cannot perform double-word IO R/W multiple sector transfer: not supported DMA: not supported PIO: pio0 So I am looking for an utility that will fix the internal fragmentation of the card. I think that is the problem. If I find out more, I will do a complete writeup!