Slow speen when coping off SD card from the drone over USB.

[Drizz]

Hi Guys,
I just got the Samsung 128 Evo Plus SDXC with read speeds of 100MB/s on paper.

When I connect to the drone itself to copy using the supplied Dji USB cable to my PC I get a max transfer speed of 37MB/s.

When I pull the card and use a memory card slot on a laptop I get 87MB/s.

Just wondering if anyone else is seeing this speed on the Air? Takes a fair swack of time to copy a lot of video off the drone.

 

[renogeno]

Write speeds using a USB cable will rarely exceed 40MB/sec even though theoretically can be @ 640 MB/s with USB 3. You seem to be close to optimum.

 

[Drizz]

Write speeds using a USB cable will rarely exceed 40MB/sec even though theoretically can be @ 640 MB/s with USB 3. You seem to be close to optimum.

You mean read speeds?

I am reading off the drone and writing to my PC/laptop

As a comparison I have an external USB 3 SSD HDD using the same port on the PC I get close to 400 MB/s both ways.

I guess there is a bottleneck inside the drones SDcard bus, as the drone is the limiting factor. The microSD card performs much faster when using a memory card reader connected to the PC for example.

 

[renogeno]

Yes, I agree....But it really doesn't matter about read speed as long as it's faster than write speed. ( that's the limiting factor) USB is limiting the write speed, thus faster transfer using card reader. A SSD doesn't have the bottlenecks, so, much faster.

 

[Miller_Drone]

For the Mavic... the USB cable in the box only works as fast as USB 2.0, and the port on the drone is micro USB which max's out at 2.0 speeds as well. You won't see USB 3.0 speeds from the drone over a cable no matter what you do.

I do all my stuff on a Microsoft Surface Pro 4, which has a microSD port... so I have to do the thumbnail card shuffle. Transferring those videos over a cable could take a half hour or more depending on video quantity and size.