USB Data Transfer Speed

[Chuck715]

Hopefully, this isn’t all old news, but I’ve had a Mavic Platinum Pro for the past 3 years and always transferred data from the drone to my computer vis the micro USB port on the drone. The best transfer speed could get was 7 MBps, that’s mega BYTES per second. The transfer rate took almost as long as the length of the video itself. In December I got a M2P, which is awesome, and has the USB-C type USB port. I bought a cable rated as 480 Mbps, that’s mega BITS per second, which seemed sufficient to me. My computer is newer and has what is called SS USB ports which have blue markings at the port. Anyway, without getting into all the technical specs regarding the USB 2.0 and 3.0 protocols, the original USB-C cable I bought transferred data at 30 MBps, over 4 times faster than my MPP, so I was very happy. To make a long story short, it occurred to me that maybe a better cable would give me even faster transfer rates. I wasn’t sure what protocols the M2P’s USB port would use (eg 2.0 or 3.0) but I ordered a USB-C cable rated for 10 Gbps and tried it. I was surprised when my data transfer speed jumped from 30 MBps to 70 MBps! So the M2P must be able to speak at a higher protocol depending on the cable used. Just saying, you may want to check it out. I prefer using the USB port rather than taking out the SD card each time and dealing with that teeny tiny thing.

https://www.amazon.com/dp/B09WKFH1Y9?psc=1&ref=ppx_yo2ov_dt_b_product_details

 

[Yorkshire_Pud]

What's the transfer rate if you put the card in a reader attached to the computer?

 

[brett8883]

Hopefully, this isn’t all old news, but I’ve had a Mavic Platinum Pro for the past 3 years and always transferred data from the drone to my computer vis the micro USB port on the drone. The best transfer speed could get was 7 MBps, that’s mega BYTES per second. The transfer rate took almost as long as the length of the video itself. In December I got a M2P, which is awesome, and has the USB-C type USB port. I bought a cable rated as 480 Mbps, that’s mega BITS per second, which seemed sufficient to me. My computer is newer and has what is called SS USB ports which have blue markings at the port. Anyway, without getting into all the technical specs regarding the USB 2.0 and 3.0 protocols, the original USB-C cable I bought transferred data at 30 MBps, over 4 times faster than my MPP, so I was very happy. To make a long story short, it occurred to me that maybe a better cable would give me even faster transfer rates. I wasn’t sure what protocols the M2P’s USB port would use (eg 2.0 or 3.0) but I ordered a USB-C cable rated for 10 Gbps and tried it. I was surprised when my data transfer speed jumped from 30 MBps to 70 MBps! So the M2P must be able to speak at a higher protocol depending on the cable used. Just saying, you may want to check it out. I prefer using the USB port rather than taking out the SD card each time and dealing with that teeny tiny thing.

Amazon.com

Yes. You possibly might be able to get faster speeds from a better micro usb cable, at least in theory. I would go to an actual computer store such as micro center to buy one and you specifically want a data cable. There are a lot of cables out there, especially on Amazon, that have been mislabeled to say they support higher speeds than they actually do. Most people just buy them for charging or won’t notice the slower speeds and so the seller gets away from it. When I was buying cables on Amazon only about 1 in 4 were actually were what they were advertised as.

I have used the micro usb on the Mavic Pro to transfer videos in a pinch and it was slow but I don’t remember it being as slow as the actual video themselves.

 

[Not A Speck Of Cereal]

A card reader is really the way to go, faster and easier.

 

[Chuck715]

What's the transfer rate if you put the card in a reader attached to the computer?

My notes from when I was testing the speed of various methods of transfer said I was getting 20 MBps via the SD card adapter thing and plugged it in to the SD slot on my computer. Not sure if that is what you mean by reader, or if it is a separate box designed to read SD cards.

 

[Chuck715]

A card reader is really the way to go, faster and easier.

What actual speeds do you get on your file transfers using a card reader?

 

[Not A Speck Of Cereal]

What actual speeds do you get on your file transfers using a card reader?

I just tested with a MicroSD I have here and here's the result, about 7GB, 760 MP3 files of 5-10MB in size (larger video files will probably copy faster).

Note: this is a read-FROM the SD card reader (which is most relevant to the conversation here, rather than a write-to), but I copied TO an NVMe SSD. If you copy to a slower hard drive, you may see slower speeds as the hard drive may be the bottleneck.

In that case, you should then test a) copy from the drone via USB and b) copy with a card reader, both to that same hard drive, to have an actual comparison.



Chris

Edit: in case the graphic can't be read, it's showing a transfer speed of ~80 MB/s at the time of the screen cap. The average will be slower. I'll try to test that later today with another tool to get the actual average AND for a folder of video files.

 

[Chuck715]

Yes. You possibly might be able to get faster speeds from a better micro usb cable, at least in theory. I would go to an actual computer store such as micro center to buy one and you specifically want a data cable. There are a lot of cables out there, especially on Amazon, that have been mislabeled to say they support higher speeds than they actually do. Most people just buy them for charging or won’t notice the slower speeds and so the seller gets away from it. When I was buying cables on Amazon only about 1 in 4 were actually were what they were advertised as.

I have used the micro usb on the Mavic Pro to transfer videos in a pinch and it was slow but I don’t remember it being as slow as the actual video themselves.

I was recording 4k@ 30 fps on my MPP which resulted in a 4GB file for 9 minutes of video. Transferring a couple files took 10 to 12 minutes for 18 minutes of video. Just painfully slow. As for the new cable I just bought, I must have got lucky that it supported the higher USB speeds.

 

[Chuck715]

I just tested with a MicroSD I have here and here's the result, about 7GB, 760 MP3 files of 5-10MB in size (larger video files will probably copy faster).

Note: this is a read-FROM the SD card reader (which is most relevant to the conversation here, rather than a write-to), but I copied TO an NVMe SSD. If you copy to a slower hard drive, you may see slower speeds as the hard drive will be the bottleneck.

In that case, you should then test a) copy from the drone via USB and b) copy with a card reader, both to that same hard drive, to have an actual comparison.

View attachment 160107

Chris

So if I'm getting 70 MB/s through the USB-C port on the drone, that's pretty close to what you are getting with the card reader. I may make 5 flights in a day and want to check the video after each flight and taking that micro SD card out 5 times, getting that little flap cover open and re-closed on the drone 5 times..., for me its just simpler to plug in the USB. But I get your point.

 

[brett8883]

As for the new cable I just bought, I must have got lucky that it supported the higher USB speeds.

Not necessarily. You bought a cord that says it can handle 10 Gbps (~1,250MB/s) and so far you’ve only gotten 70MB/s from it. It’s very possible the SD card or the drone is the bottleneck not the cable but it’s way too soon to say you actually received a 10 Gbps cable.

 

[Chuck715]

Totally agree. My only point of this thread was to point out that a cable change alone more than doubled my transfer speed with all other factors remaining the same (ie same drone, SD card and computer). Thanks for your input.

 

[Not A Speck Of Cereal]

I did some side-by-side comparisons.

TL;DR: the Card Reader copy was faster than the USB copy by many factors. I probably could double my USB copy speed by getting a better cable, but it would still be far slower.

<Start of subjective, which can be skipped>This is a purely subjective note on preference of method: when I went to hook up the drone for the USB copy, I was reminded of everything required, getting out the aircraft, pulling out the legs (to get to the ports), finding a place for it on the desk, powering it up (hopefully one always has a sufficiently charged battery, otherwise you have to power it down then get another battery), opening the USB door (yes, both the USB port and SD card slot have doors), then you can connect and copy.

To me, getting the card out without otherwise messing with the aircraft, and dealing with a small card reader on the desktop is a lot less bother. <End of subjective>.

SD CARD: exact same card used in all copies with identical 82 files of ~30GB video

USB hardware:

• Anker USB-C to USB-A Cable:
  • https://www.amazon.com/gp/product/B07DC5PPFV
• plugged into computer front panel USB port (connected to motherboard with no USB hubs between)

CARD READER hardware:

• Sony MRW-S1 SD card reader:
  • https://www.amazon.com/gp/product/B071FJRXGX
• plugged into same front-panel USB port as USB (mentioned above)

METHOD OF COPY:

• Robocopy utility, comes with Windows (command-line batch file tool)
  • Example command line use:
• robocopy "%SourceFolder%" "%TargetFolder%" /MT:24 /E /NP /TEE /LOG:log.txt
• where
  • %SourceFolder% = drive-letter \ path of video files on source (drone or card reader)
  • %TargetFolder% = drive-letter \ path of destination (same destination drive for both copies)

RESULTS (copied from summary at bottom of each robocopy log):

• USB results:

Times : 6:07:15 0:15:06​

​

Speed : 36,731,183 Bytes/sec.​

Speed : 2,101.775 MegaBytes/min.​

• CARD READER results:

Times : 0:45:29 0:02:10​

​

Speed : 255,081,725 Bytes/sec.​

Speed : 14,595.894 MegaBytes/min.​

The card reader was ~8 times faster for totals (first number), ~7 times faster for per file averages (second number).

That's 255 MB/s vs 36 MB/s. If I got a better USB cable to double the speed (reportedly being around 70 MB/s. though I'm not sure of the method used to derive that number), the card reader copies would still be about 3-4 times faster.

[ Earlier in this thread, I reported 80 MB/s when I did a simple Windows copy and screen-capped the progress dialog while it was still copying, which is not a very test worth method. I don't know why that reported slower, but it was a completely different method from ROBOCOPY at the command-line, and of course I used the same ROBOCOPY method for both USB vs Card reader compares above. ]

I RAN EACH ROBOCOPY TEST 3 TIMES TO CONFIRM SPEEDS. If you're comfortable around batch files, this is an easy test to do yourself (requires all hardware mentioned above, of course). You can use another copy method as long as you get a good average at the end and use the same copy method for both tests.

ONE MORE REASON NOT TO USE THE USB PORT FOR FILE TRANSFER: if the USB-C port on the aircraft is the only method of connecting the aircraft to the computer for use of analytic, configuration, and calibration tools (such as DJI ASSISTANT), then I wouldn't want to wear it out by using that port for file transfer.

This is the same reasoning I use with the RC side USB port, which I only use for charging. I use the RC's bottom USB port for flying, because many people have broken the side port using it for flying due to it's fragile connection to the RCs internal PCB.

Chris

 

[brett8883]

I did some side-by-side comparisons.

TL;DR: the Card Reader copy was faster than the USB copy by many factors. I probably could double my USB copy speed by getting a better cable, but it would still be far slower.

<Start of subjective, which can be skipped>This is a purely subjective note on preference of method: when I went to hook up the drone for the USB copy, I was reminded of everything required, getting out the aircraft, pulling out the legs (to get to the ports), finding a place for it on the desk, powering it up (hopefully one always has a sufficiently charged battery, otherwise you have to power it down then get another battery), opening the USB door (yes, both the USB port and SD card slot have doors), then you can connect and copy.

To me, getting the card out without otherwise messing with the aircraft, and dealing with a small card reader on the desktop is a lot less bother. <End of subjective>.

SD CARD: exact same card used in all copies with identical 82 files of ~30GB video

USB hardware:

• Anker USB-C to USB-A Cable:
  • https://www.amazon.com/gp/product/B07DC5PPFV
• plugged into computer front panel USB port (connected to motherboard with no USB hubs between)

CARD READER hardware:

• Sony MRW-S1 SD card reader:
  • https://www.amazon.com/gp/product/B071FJRXGX
• plugged into same front-panel USB port as USB (mentioned above)

METHOD OF COPY:

• Robocopy utility, comes with Windows (command-line batch file tool)
  • Example command line use:
• robocopy "%SourceFolder%" "%TargetFolder%" /MT:24 /E /NP /TEE /LOG:log.txt
• where
  • %SourceFolder% = drive-letter \ path of video files on source (drone or card reader)
  • %TargetFolder% = drive-letter \ path of destination (same destination drive for both copies)

RESULTS (copied from summary at bottom of each robocopy log):

• USB results:

Times : 6:07:15 0:15:06​

​

Speed : 36,731,183 Bytes/sec.​

Speed : 2,101.775 MegaBytes/min.​

• CARD READER results:

Times : 0:45:29 0:02:10​

​

Speed : 255,081,725 Bytes/sec.​

Speed : 14,595.894 MegaBytes/min.​

The card reader was ~8 times faster for totals (first number), ~7 times faster for per file averages (second number).

That's 255 MB/s vs 36 MB/s. If I got a better USB cable to double the speed (reportedly being around 70 MB/s. though I'm not sure of the method used to derive that number), the card reader copies would still be about 3-4 times faster.

[ Earlier in this thread, I reported 80 MB/s when I did a simple Windows copy and screen-capped the progress dialog while it was still copying, which is not a very test worth method. I don't know why that reported slower, but it was a completely different method from ROBOCOPY at the command-line, and of course I used the same ROBOCOPY method for both USB vs Card reader compares above. ]

I RAN EACH ROBOCOPY TEST 3 TIMES TO CONFIRM SPEEDS. If you're comfortable around batch files, this is an easy test to do yourself (requires all hardware mentioned above, of course). You can use another copy method as long as you get a good average at the end and use the same copy method for both tests.

ONE MORE REASON NOT TO USE THE USB PORT FOR FILE TRANSFER: if the USB-C port on the aircraft is the only method of connecting the aircraft to the computer for use of analytic, configuration, and calibration tools (such as DJI ASSISTANT), then I wouldn't want to wear it out by using that port for file transfer.

This is the same reasoning I use with the RC side USB port, which I only use for charging. I use the RC's bottom USB port for flying, because many people have broken the side port using it for flying due to it's fragile connection to the RCs internal PCB.

Chris

One thing to keep in mind is you must have used a full sized SD card because there’s no way you could have gotten 255 MB/s using a micro SD card.

Using a thunderbolt 3 card reader connected to a thunderbolt 4 port which can easily transfer my Cfexpress cards at 500+ MB/s I was only able to get a maximum of 86 MB/s with a Sandisk Extreme 16 GB micro SD card.

There might be slightly faster micro SD cards out there but I think we can take ~86 MB/s average as the benchmark read speed of a micro SD. If he was able to get 70 MB/s from the USB-C on the drone in a real life application, not a benchmark test, I think we can say there’s not a huge difference in performance between an SD card reader and reading from the drone. Your other points still apply

 

[Not A Speck Of Cereal]

One thing to keep in mind is you must have used a full sized SD card because there’s no way you could have gotten 255 MB/s using a micro SD card.

I assure you that I didn't. After doing the USB test, I took the micro out of the drone, put it in the full-size adaptor, and put that in the card reader. The very same MicroSD card.

EDIT the SD card I used is a V30, U3, A2 64GB Sandisk Extreme.

Chris

 

[brett8883]

I assure you that I didn't. After doing the USB test, I took the micro out of the drone, put it in the full-size adaptor, and put that in the card reader. The very same MicroSD card.

Chris

Interesting. There may be something wrong with my card then . I’ll have to try some other tests

 

[Not A Speck Of Cereal]

Interesting. There may be something wrong with my card then . I’ll have to try some other tests

At the end of the day, it doesn't matter. It's not the difference between your machine and mine, but the difference between the 2 copy methods both performed on your machine. If they're near the same, it boils down to subjectives for you.

There is a large number of potential differences we aren't even considering, what version and speeds of PCI/PCH on your motherboard (and level of PCI support on your CPU). I don't even know if you are running Windows or Mac. My machine has 128GB of system memory, which also might help.

A story: a few months back, I put a Thunderbolt 3 card in a Windows PC for music production / audio recording. This ASUS card was made *for* my motherboard (ASUS ThunderboltEX 3-TB on an ASUS Z490-A). After plugging it in and turning on all of the BIOS settings, it didn't work for sh(manure)t, just unworkable with all the latency. VSTs (soft synths) just shut the audio driver down completely.

Longer story short, after several more BIOS changes (those *not* on the Thunderbolt BIOS page) and several Windows settings changed (especially PCI Express, Link State Power Management, Setting: OFF). I was finally getting Thunderbolt performance.

You did say "Cfexpress cards at 500+ MB/s" so maybe my story example isn't the difference for you, but my point is there are many things that could explain differences.

My card reader is UHS-II compatible, but the MicroSD cards and adaptors don't have that kind of support. However, it could still be a faster card reader than the one you have built in (I think that's what you said you had).

My comparisons were just to show what differences I am getting between the methods. Good luck on finding what the differences are on your system.

Chris

 

[Xitor]

Late to respond here because I got excited and ordered the cable, but had to wait for it to come in to provide results:

	Ave MB/s
Standard USB3 cable (USB 3.2 port)	31
Recommended USB3 cable (USB 3.2 port)	31
USB 3.2 USB reader in USB 3.2 port:
MicroSDXC PNY256GB, Class 10, A1, U3, V30 (rated 100MB/s)	86
MicroSDXC Lexar 256GB U3, A2, V30 (rated 160 MB/s)	122

So unfortunately I didn't get any better speed with the recommended cable, perhaps because I already had a good cable, but, using a USB 3.2 SD reader in my 3.2 USB port was definitely the best performance for me.

The A2 SD card was a last minute test, surprised at the difference. Almost 4X what I get with the cable, nearly 50% better than the A1 card, so definitely going that route from now on.

 

[Chuck715]

Late to response here because I got excited and ordered the cable, but had to wait for it to come in to provide results:

	Ave Mbs
Standard USB3 cable (USB 3.2 port)	31
Recommended USB3 cable (USB 3.2 port)	31
USB 3.2 USB reader in USB 3.2 port:
MicroSDXC PNY256GB, Class 10, A1, U3, V30 (rated 100MBps)	86
MicroSDXC Lexar 256GB U3, A2, V30 (rated 160 Mbps)	122

So unfortunately I didn't get any better speed with the recommended cable, perhaps because I already had a good cable, but, using a USB 3.2 SD reader in my 3.2 USB port was definitely the best performance for me.

The A2 SD card was a last minute test, surprised at the difference. Almost 4X what I get with the cable, nearly 50% better than the A1 card, so definitely going that route from now on.

Interesting data. It seems like the SD reader is really the fastest method. I am surprised you didn't get better speed with that recommended cable. I am using a SanDisk 128GB Micro SD A2 U3 V30 rated at 160MB/s in my drone and I consistently got the 30MBps with my USB2 cable and jumped to 70MBps with the USB3 cable. Maybe our computers are causing the difference. Oh well, sorry you bought the cable for nothing.

 

[Xitor]

Interesting data. It seems like the SD reader is really the fastest method. I am surprised you didn't get better speed with that recommended cable. I am using a SanDisk 128GB Micro SD A2 U3 V30 rated at 160MB/s in my drone and I consistently got the 30MBps with my USB2 cable and jumped to 70MBps with the USB3 cable. Maybe our computers are causing the difference. Oh well, sorry you bought the cable for nothing.

You can never have too many good USB cables. These are also shielded very well. Also, the A2 test was a last minute thought from my gopro SD card, I bet you're right that with that card in the drone I would have got similar rates. At least for my case though, even if it hit 70, the A2 in USB 3.2 hits 122 so more than 50% increase. Glad I tested though, I didn't realize the A1-A2 made such a big difference, was using A2 only in GoPro but getting one now for my drone too.

 

[Not A Speck Of Cereal]

You can never have too many good USB cables. These are also shielded very well.

(Looks at my several drawers of various cables)

Chris