Fujifilm X-T30 and Sandisk Extreme Pro 128GB SDXC Card 128GB 170MB/s V30 UHS-I U3

Average speed is 15.6 MB/s.

I am using a usb 3.1 gen 1 cable plugged into a usb 3 port to transfer the photos. 15.6 mb/s no where near what is neither advertised for this sd card nor usb 3 speed. What am I doing wrong? Maybe an sd card reader would be faster but are these speeds normal?

  • 3
    \$\begingroup\$ I’m voting to close this question because it appears to be a computer/data-transfer issue rather than a photographic issue. \$\endgroup\$
    – Tetsujin
    Sep 14, 2020 at 11:55
  • 1
    \$\begingroup\$ We've answered essentially the same question here several times already. Have you tried to find an answer in the existing base of questions and answers? (Hint: it's almost always a substandard cable.) \$\endgroup\$
    – Michael C
    Sep 15, 2020 at 3:27
  • \$\begingroup\$ What OS are you using? This is roughly the performance I get when transferring exFAT volumes which is about 10X slower that FAT32. It seems like the exFAT driver has plenty of catching up to do. In any case, using a card reader is the better approach and costs so little that it's not worth much time to investigate a complex interaction of software and hardware components. \$\endgroup\$
    – Itai
    Sep 19, 2020 at 1:03

1 Answer 1


There are plenty of possible bottlenecks...

  • The camera electronics
  • Your local USB driver
  • Your filesystem (on a full/fragmented disk things can take a lot longer)
  • Your disk (SSD or HDD?)

Personally I have always found that connecting to the camera was a lot slower than taking the card out and using a SD card reader(*). Currently using a cheap (€7) card reader from Amazon in a USB3 port of my PC, I get transfer speeds around 80Mbytes/sec to my SSD from a Sandisk Extreme 32GB cards.

(*) Another purpose of that routine is to swap cards in the camera to even out the wear over my set.

  • \$\begingroup\$ I doubt fragmentation is an issue on solid state devices - there are no moving parts \$\endgroup\$
    – wilkgr
    Sep 14, 2020 at 22:20
  • \$\begingroup\$ @wilkgr There are no moving parts - but there is an onboard controller that constantly changes addresses to physical locations when they are "available" for recording data on the chips to facilitate wear leveling. Even solid state devices take longer to read files that are fragmented than files that are recorded sequentially. \$\endgroup\$
    – Michael C
    Sep 15, 2020 at 3:31
  • \$\begingroup\$ @MichaelC Ahhh my bad. I hadn't looked into this recently, only when SSDs only came out. \$\endgroup\$
    – wilkgr
    Sep 15, 2020 at 7:04
  • \$\begingroup\$ Flash memory has always been that way, even before SSDs were a thing over a decade ago. \$\endgroup\$
    – Michael C
    Sep 15, 2020 at 23:00
  • \$\begingroup\$ @MichaelC When SSDs as a standard PC component was new and I was a lot younger, a lot of magazines I read at the time ran articles that mentioned that SSDs don't need defragmenting, which is what I was thinking of. \$\endgroup\$
    – wilkgr
    Sep 17, 2020 at 2:46

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