Samsung Galaxy Note 8 SMB and USB 3.1 file transfer speeds

The Samsung Galaxy Note 8 is a great device with a complicated USB port. I’ve written this page to inform you about any possible slow USB and SMB file transfer speeds, and how you should be able to circumvent these issues. The most important thing to realise is that the device is capable of being fast i.e. there’s no hardware limitation preventing SMB or USB from being fast; please do not let this page sway you from buying the Samsung Galaxy Note 8. In my opinion, it’s a great phone with quirks that can be overcame.

Incredibly slow Windows file shares (SMB) with the Samsung Galaxy Note 8

When connecting to a windows computer i.e. mapping a file share via the use of SMB, the Samsung Galaxy Note 8 demonstrates incredibly slow file transfer speeds. It seems this issue is present with many Samsung devices and possibly phone’s made by other brands–information like this is hard to obtain. My theory is that this is some kind of power saving feature. Interestingly you can speed up the file transfer speed if you download a file from a webpage and then download a file via SMB at the same time. I suspect this is the equivalent of running a game on a desktop computer to kick the processor into speeding up, and then opening another program at the same time. This method is pretty nasty as a solution but it proves a key bit of evidence–the network facilities are capable of being fast–and it is useful to see what kinds of speeds the device supports. If you have no other programs open, you open the file browser and copy a file, speeds from about 600KB/sec to 1MB/sec are quite common and this isn’t really acceptable. If you want to copy a large media file saved on another computer, and watch it on your phone, this could be problematic.

The good news here is that there’s various ways to circumvent this issue. For downloading files, FTP is considerably faster. Windows server doesn’t support SFTP (it does support FTPS) as a native option but there are programs available which will let you install it. Moreover, you might not deem SFTP as necessary.

If streaming the file is an option, using a media player like VLC will give you faster network speeds. For watching movies and whatnot, you should also consider a program called “servio.” You can prevent it from doing any transcoding and use it purely to pass the file; the server CPU load does not seem to increase when servio is in use, but when the file is playing on the Samsung Galaxy Note 8, you might find the bandwidth the phone uses is considerably superior (I’ve maxed out my Raspberry Pi’s WiFi speed for example) to using a Windows SMB file share with certain media players. You should have no problem streaming a bluray movie with this method providing your WiFi speed is adequate.

It would be nice if Samsung gave the option to increase SMB share speeds; I know for certain the hardware supports it. If it was a setting in performance mode, it would please a lot of users. The method above basically boils down to me saying use the right tool for the job. If you want to transfer files, use FTP. If you want to stream movies, use a streaming program like servio. I am not saying this is acceptable (other devices treat files in a superior way) but I am saying there is a pragmatical solution to the problem.

Use a Linux machine as a file sharing device

A more complicated way to share files is to have a separate machine–it can be virtual–running Linux. Then map the Windows device to the Linux share, and then SFTP into the Linux device from the phone. It sounds awfully complicated, but if you’re fairly tech savvy (which I assume you are, to be caring about this stuff in the first place), it won’t be too difficult to set up. You don’t necessarily need any hardware and you won’t have to pay a penny. CentOS or Debian (they’re Linux distributions) are freely available and you can also get freely available virtualisation technology to run these operating systems within Windows. Alternatively, you could map a share to a Raspberry Pi and have your Raspberry Pi act as not only a Wireless Access Point but also a media sharing device.

Assuming you’ve already set up Debian or CentOS Linux with an SSH Key and know how to log into the device (read up until line 21 for Debian), you then just need to map your Windows shares.

For Debian , install the relevant programs and make the sharing folders:

Edit file share information:

Create a share credentials file:

By doing it this way, you can then SFTP into the Linux device using an SSH Key and you’ll also reap the benefits of a fast network file share.

USB Type C USB 3.1 on the Samsung Galaxy Note 8

If you don’t want to read all of this, please read the bullet points:

  • I have achieved 70MB/sec+ speeds writing to the phone from a device connected to the USB port of the Samsung Galaxy Note 8
  • USB Speeds drop significantly, down to as low as 13MB/sec, when multiple devices are connected
  • The MicroSD card slot is fast and runs at USB 3.1 speeds
  • It’s quicker to copy files from an external SD card reader to the MicroSD card slot, and back again to a different SD card than it is to copy files from an SD card to a MicroSD card on the same USB card reader
  • If you’re looking for a portable backup solution to add to your professional camera, look no further but be aware of its USB limitations
  • You can load raw photographs quickly
  • You can edit raw photographs

Please don’t be too alarmed by what I’m about to say below. For the average user that has zero interest in plugging in multiple high speed USB devices, this will not affect them.

USB 3.1 isn’t always USB 3.1

The USB C USB 3.1 port on the Samsung Galaxy Note 8 isn’t always USB 3.1. I could be wrong, but it’s as if Samsung have implemented a crafty measure to slow the USB port as a means to lower current draw from the battery and therefore minimise heat (if you know about last year’s disaster, you probably know where I’m going with this theory…)

It’s not mentioned in the documentation anywhere and USB C USB 3.1 phones are of interest to me as I can use them as a portable backup device for my Sony a7rII camera (taking a laptop isn’t an option on long hikes.)

It’s not all doom and gloom though:

If you’re just plugging in the one USB device e.g. an SD card reader, and you copy files from that device to the onboard storage or the built in microSD card, you will receive full USB 3.1 speeds (my cards aren’t super quick, but I’ve gotten over 70MB/sec so I know it’s not using USB 2.0, for sure.)

Here’s the problem though… If you plug in a memory card reader with dual slots, with the intention to move files from a large SD card to a microSD card (NOT the built in microSD card reader) on the same USB reader, i.e. a hub of sorts, then it will revert to USB 2.0 speeds.

Some people have tested a few devices, noticed that a Samsung T5 SSD is fast and that their third party HUB is slow, and then made the assumption that the Samsung Galaxy Note 8 (actually I think the comment I read was about the Samsung Galaxy s8+ but the same logic applies) favours Samsung’s own equipment. From what I can tell this is not true at all–non causa pro causa.

The limitation is based around the number of devices, not the brand of device. It could be entirely a software based limitation as the phone has the hardware to work in USB 3.1 mode; however, I’m not sure either way. I suspect the port doesn’t supply the same amount of current as last years model.

There are a few ways to make a battery explode, 1) short it. 2) short it by crushing it. 3) discharge it incredibly fast. 4) charge it incredibly fast. 5) discharge it fast enough to expand and crush itself (if there’s not enough room in the case). 6) charge it fast enough to expand and crush itself (if there’s not enough room in the case).

The battery undoubtedly has more room in the case compared to last years model, and by limiting the amount of current to the USB port, it would be far less likely to discharge too quickly. In other words, I suspect they’ve gone safety mad. I’d be fine with that if they informed the user, but there’s no mention of this anywhere.

USB card reader information


USB card readers are mostly bad and most of them do not support sequential writes, but I have found a few decent ones.

When I connect my SD card reader to my computer, as a reference, the speeds slow up a bit and the card reader gets quite hot when writing from one card to another sequentially. With the Samsung Galaxy Note 8, the speeds can drop to as low as 13MB/sec after a lot of writing, (that’s 26MB/sec total USB throughput  as they’re both on the same port.)

There are two ways to think about this problem…

Two examples of how to transfer data can be seen in the diagram above. The last one shows data going from a large SD card to a MicroSD card on the same SD card reader. If you look at the screenshots below, the first one shows sustained sequential writing from an external SD card to an external MicroSD card. It’s not great.

The SD to phone photograph shows the kind of speeds I’ve achieved with the USB port i.e. 70MB/sec+ when only one device is connected. The SD to MicroSD picture is on the breaking point of maximum USB 2.0 speeds, but I suspect the limitation here is with the speed of the MicroSD card in the phone itself rather than it being limited to USB 2.0.

If you look at the MicroSD phone to SD speeds, this is faster than USB 2.0; in other words, I believe the MicroSD card slot in the Samsung Galaxy Note 8 phone supports USB 3.1 speeds, and a single device connected to the USB port also supports USB 3.1 speeds. Not only that, but when data is transferred from USB to the MicroSD card in the Samsung Galaxy Note 8 phone, the sustained writes do not seem to dip. They’re respectable, and remember, 70MB/sec writing is actually 140MB/sec total throughput.

My advice is to buy a case which allows you to access the MicroSD card easily and copy files from an SD card reader to the MicroSD card in the phone. Alternatively, buy a large 128GB MicroSD card or greater. Use 64GB for phone storage, and 64GB as a buffer. Copy files from a 64GB SD card to the MicroSD card in the phone. Then plug in a different SD card or even a Samsung T5 SSD, and copy the files from the MicroSD card in the phone onto the second device.

You can leave the MicroSD card in the Samsung Galaxy Note 8 at all times with the latter method; the only reason I suggest this method is because most phone cases are abominations and do not let you access the MicroSD card slot very well. If you have access to the MicroSD card slot with your phone case or you don’t mind removing your case frequently, then you might as well put a fresh 64GB MicroSD into the Samsung Galaxy Note 8 phone and copy the files from an external USB card reader onto it.

I do not own a Samsung T5 SSD, so I cannot be certain what the speeds are; however, the MicroSD in the phone to an SD card gives you 60MB/sec+ write rates, combine that with the first card at about 50-55MB/sec, and then half the value (as you’ll be copying to two separate places), and you could still be looking at 30MB/sec+ sustained write rates. Moreover, when raw photographs are on the MicroSD card in the phone, you can open them quickly. I would really like to get my hands on a Samsung T5 SSD as I’m curious as to how quickly you can edit photographs on that thing.

Remember, USB 2.0 is 60MB/sec maximum theoretical speed on one port (which you’d have to half if you’re copying from one device to another), so you’re still breaking USB 2.0 speeds in pragmatical terms with this method and you get the choice of being able to copy to an SD card, MicroSD or an external SSD. With sequential writing on the same memory card reader, you’re pretty much limited to SD card to MicroSD.

File transfer conclusion

The USB port is amazingly fast when transferring files to the built in MicroSD card but you may have to remove the MicroSD card semi frequently. If you want to copy files from an external device to another external device, I believe the best method is to use the MicroSD card slot in the phone as a buffer.

Please read my Samsung Galaxy Note 8 review if you are interested in the phone.

2 thoughts on “Samsung Galaxy Note 8 SMB and USB 3.1 file transfer speeds”

  1. Great info, thanks , a question you test with a voltimeter usb the power out in case when detected the usb 2, and usb 3? I need conect a external monitor usb, like the asus asus MB16B and not kill the battery’s phone.

    1. I don’t have a voltmeter so I haven’t tested, sorry. You can plug in a mains powered monitor via USB but I haven’t tested a monitor being powered from the USB port itself. If the Asus MB16B has its own power source, I would assume it would work but I cannot be 100% certain.

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