Samsung Galaxy Note 8 SMB, USB 3.1 file transfer speeds

The Samsung Galaxy Note 8 and the Samsung Galaxy Note 9 are great phones with a complicated USB port and SMB behaviour (especially when remotely connected to a windows machine) under certain configurations. I’ve created this page to help people suffering from slow USB and SMB file transfer speeds. I can confirm these SMB issues are present with the Samsung Galaxy Note 9 and not just the Samsung Galaxy Note 8. Discovering all of this has cost me a lot of time and money, so I’d like to pass my knowledge along. If you can spare £1/$1, it would help me write future technical pages like this :).

The most important thing to take from this article is that there’s no hardware limitations preventing SMB or USB from functioning at their rated specification (USB 3.1).

Please do not let this page sway you from buying the Samsung Galaxy Note 8. I suspect the Samsung Galaxy s9 exhibits the same behaviour, so hopefully if I write Samsung Galaxy S9 in my article somewhere, Google will pick up on it. Perhaps any Samsung Galaxy s9 owners can let me know their findings.

I have a server in my house and it runs virtual computers amongst other things:

  • A VPN service for my phone to connect to. Most of this was preconfigured and downloadable for free (this isn’t required or relevant to this article but it’s cute and you should take a look). Unfortunately people think of VPN’s as proxies these days. I use it so I can access my files from anywhere, as if I was at home.
  • A virtual sharing box which maps windows shares via SMB. The phone then connects to this via SFTF i.e. it acts as a gateway. Windows machine –> Linux –> Phone. You don’t need a server for this, you can run it on your desktop.
  • For my Sony a7rII camera, I backup my photographs using a SanDisk Extreme Portable 500GB SSD (the newer model) and I have a few MicroSD cards and SD cards if need be. This is fairly fast (USB 3.1 but I’m limited by the speed of the card, in my case 100MB/sec MicroSD cards) but there’s a faster method I didn’t know about at the time of buying these.
  • I also have a RaspberryPi, and it acts as a Wireless Access Point (this isn’t required or relevant to this article).

As you can tell from this list, I’m a bit of a nerd. Some of it was fun to set up, so it might give you a bit of creative inspiration. I digress…


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

Mapping a file share via the use of SMB to a windows computer, using the Samsung Galaxy Note 8, demonstrates incredibly slow file transfer speeds. This issue is present with many Samsung devices and possibly phone’s made by other brands–information like this is hard to obtain. I suspect the Samsung Galaxy S8, Samsung Galaxy S9 and the Samsung Galaxy Note 8 are all affected by this. Android uses a slightly older version of SMB. My theory–Samsung implemented a power saving feature–it is just a theory. Interestingly, you can speed up file transfers by downloading a file from a webpage while your SMB file transfers. 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. It’s no solution but it provided me with evidence when deciphering some of this gibberish–the network facilities are capable of being fast. By default, if you have no programs open, and you copy a file, expect to see speeds from about 600KB/sec to 2MB/sec. If you want to copy a large media file saved on another computer, and watch it on your phone, this could be problematic.

There’s various ways to circumvent this issue. FTP is considerably faster. Windows server doesn’t support SFTP (it supports FTPS) as a native option but there are programs available that 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 might want to 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 when directly connected to a windows machine; I know for certain the hardware supports it but I don’t know if android does. If it was a setting in performance mode, it would please a lot of users. The method above basically boils down to using different tools for the job. It’s not ideal, and I don’t really recommend it but that’s one option.

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. This is the method I recommend. You map the Windows device to the Linux share, and then SFTP into the Linux device from the phone. It’s more secure if you’re using the internet to access your files (SFTP can be accessed with SSH keys). It sounds awfully complicated, but if you’re fairly tech savvy (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:

apt-get install cifs-utils

mkdir /root/photos
mkdir /root/videos
mkdir /root/downloads

Edit file share information:

nano /etc/fstab

//X.X.X.X/downloads /mnt/network/X cifs credentials=/root/share,uid=108,gid=113 0 0
//X.X.X.X/photos /mnt/network/X cifs credentials=/root/share,uid=108,gid=113 0 0
//X.X.X.X/videos /mnt/network/X cifs credentials=/root/share,uid=108,gid=113 0 0
/dev/sdb       /mnt/downloads    ext2    defaults    0

Create a share credentials file:

nano share


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.

If you have problems with this and it doesn’t auto mount, try the code below…

//X.X.X.X/X /mnt/X/X cifs credentials=/root/share,auto,rw,uid=1000,gid=1000,comment=systemd.automount 0 0
//X.X.X.X/X /mnt/X/X cifs credentials=/root/share,auto,rw,uid=1000,gid=1000,comment=systemd.automount 0 0

Using this methos with a virtual machine, I got adequate speeds of up to about 8MB/sec. My server’s ethernet is dodgy and only supports up to about 11MB/sec anyway (100mbit LAN).


  • I do not connect to my windows machine directly (unless it’s to RDP) as a means to share files, using the phone. This is slow and a bit insecure (I can manage keys and don’t have to use passwords this way).
  • To access my network share, I use my fingerprint in Solid Explorer and this connects to a Linux machine.


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 MicroSD card connected to the USB port of the Samsung Galaxy Note 8 i.e. maxed out the MicroSD card’s speed. You can get faster speeds than this if you use a Samsung T5 or an m.2 drive with an m.2 enclosure. Right now, I’d recommend the SanDisk Extreme Portable SSD.
  • USB Speeds drop significantly, down to as low as 13MB/sec, when multiple devices are connected in a way the phone dislikes e.g. multiple cards into the same card reader
  • The MicroSD card slot is fast and runs at USB 3.1 speeds
  • The MicroSD card slot in the phone is faster than the card readers I have tried
  • If you’re looking for a portable backup solution to add to your professional camera, this phone is great
  • You can load raw photographs quickly
  • You can edit raw photographs
  • I’ve tested the Samsung’s adaptors and they’re not as good as the Google USB adaptor
  • If your USB HUB has an HDMI port (left item), I believe you won’t be able to get USB 3.1 speeds
  • If you’re using a memory card reader with two cards inserted, remove a card
  • If you’re using the included Samsung USB-A to USB-C adaptors, for anything requiring a high speed transfer, use something else. These work fine for other tasks

As you can see in this photograph, I have two memory card readers, a Google USB adaptor, and my USB HUB has no HDMI port! When your USB HUB has an HDMI port, I believe the phone will switch to USB 2.0. Also, if you look carefully at the end of the plug with the Google adaptor, you will see it’s machined from one piece of metal. This doesn’t mean much, but it suggests they’ve spent more on manufacturing it. I’ve checked the speeds with it, and the Google adaptor is faster (it’s not just machined more beautifully). If your USB HUB already has a USB-C connector, you won’t be needing an adaptor I guess. I can’t really afford much, as I’ve already been robbed blind with the MicroSD cards and I want to keep my money for travelling.

The google adaptor I bought from their UK store, I don’t know if the link will work for Americans.

Samsung Galaxy Note 8 S-Pen issues

A while ago, I noticed a few people complaining about S-Pen issues on the official Samsung forum, and they were returning their phone. I replied helping them. If you’ve run into such bother, it’s likely magnetism from your phone case. I asked Samsung to include this information in an FAQ. They told me they’d reward me for helping (I literally saved Samsung thousands of dollars at the time) but I don’t know if they included it in an FAQ.

During the time this all happened, I spoke to their tech support about the fact I could not get USB 2.0 speeds from the USB port, using USB-OTG. I was advised you can only get USB 3.1 speeds when one device is connected.

I later bought a bunch of MicroSD cards, with the intention of opening my MicroSD card tray each time, and backing up photographs that way (SD card in the USB-OTG port, MicroSD in the phone–copy from one to the other). My phone case wouldn’t let me access the MicroSD port, so I bought a different case. In total, a lot of money on MicroSD cards, a case, and whatnot. Shortly after buying a bunch of MicroSD cards, I discovered the problem was likely with the HDMI port on my USB HUB. That’s how I learned this stuff :).

Even though I’m a bit short for cash at the moment, I really wanted to get to the route of the problem and so I bought an anker USB HUB. Needless to say, Samsung tech support had given me false information, they didn’t “reward” me (I don’t want to sound entitled, I never saw it was my right to be given something…technically speaking it might be from a legal standpoint since they agreed to in writing, but you get what I mean), and I really wish I had bought a portable SSD to begin with, instead of a bunch of MicroSD cards… Luckily, I was able to return some of the MicroSD cards.

  • MicroSD cards are slower but unless you’re taking a lot of photographs per day and your SD cards are a lot faster than your MicroSD cards, it might not matter as much as you think–you should also consider getting home and transferring that data onto the computer
  • If a part of your hardware fails (a card reader, the USB hub, etc.), you have a backup–your phone’s MicroSD card reader. Other than this, you could even consider a normal SD card, then you have more storage to use in your camera
  • Both SD and MicroSD cards are generally lighter and more durable than a portable SSD

For the average user that has zero interest in plugging in multiple high speed USB devices, none of this will interest 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’m not sure if Samsung have implemented something to deliberately slow the USB port as a means to lower current draw from the battery and therefore minimise heat, or what the idea is behind it.

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, 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. This is not true at all–non causa pro causa.

The limitation is based around how the phone views the device. With a dual card SD reader, it sees it as a HUB it doesn’t really like. USB HUBs with HDMI ports are also disliked. It’s not brand specific. 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.

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 it’s a bit of a safety issue. 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. You can achieve these speeds if your USB HUB does not have an HDMI port.

My advice is to either 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 Samsung T5 or an m.2 drive and an m.2 drive enclosure, an Anker USB HUB and a Google USB adaptor. Copy files from a 64GB or 128GB card to the MicroSD card in the phone or one of these drives.

You can leave the MicroSD card in the Samsung Galaxy Note 8 at all times with the latter method but you can also buy two card readers, and copy one to the other (like in the photograph above). Even though card readers often have dual slots, I have tried lots of them and none of them work well with this phone.

File transfer conclusion

The USB port is amazingly fast when transferring files to the built in MicroSD card reader but you may have to remove the MicroSD card semi frequently (it entirely depends on what size cards you buy). If you want to copy files from an external device to a micro SD card without a USB HUB, you will have to get a case that lets you open the MicroSD card tray frequently. If you want to copy files from a large SD card to a Samsung T5 or a SanDisk Extreme Portable SSD, then you will either have to buy a USB HUB without an HDMI port or use the phone/MicroSD card as a buffer. I’m not entirely sure what the best method is for you as the fastest isn’t always the most reliable. SD to SD is also a viable option, you’ll need a USB HUB, two card readers and an adaptor.

The best option is probably to use a SanDisk Extreme Portable SSD or a Samsung T5 or a make it yourself enclosure an m.2 drive, a USB HUB without an HDMI port, and 64GB or 128GB SD cards. I’d then buy a reasonable sized MicroSD card for the phone as partial backup. In the event your USB HUB breaks or doesn’t function at USB 3.1 speeds, you can copy files to the built in MicroSD card, unmount the SD card, plug in the portable SSD and copy files from the MicroSD onto the portable SSD.

SD to SD is not particularly slower than SD to SanDisk Extreme Portable SSD due to the speed of the SD card. However, when it comes to editing the photographs, that’s a different story entirely. As you can expect a huge speed increase from the SSD.

The safest method is to buy a bunch of MicroSD cards or SD cards, two card readers, and a USB HUB without an HDMI port.

If you buy an m.2 drive, make sure you buy one suitable for the enclosure. They vary slightly in shape and some are PCI Express. You should not get a PCI Express m.2 drive. You can typically tell because the speeds for those are much faster.


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

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4 thoughts on “Samsung Galaxy Note 8 SMB, USB 3.1 file transfer speeds

  • 27/05/2018 at 17:08

    Right now i connected A7riii and 1tb m.2 SSD using USB hub. They both are running at usb3.0 speeds.
    And i’m tethering A7riii to note 8 with 1tb ssd being the destination to save files.

    It performs same as SONY 64GB uhs ii u3 , memory card, maybe a tad better and tad slower depending on raw or jpeg.

    its roughly 45 sec to clear the entire buffer into ssd. Very cheaper solution compared to expensive and limited size sd cards.

    • 09/06/2018 at 12:31

      Thanks for responding to my article. I’m glad to hear that works for you :).

  • 03/12/2017 at 06:43

    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.

    • 03/12/2017 at 14:00

      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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