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I have a USB 3.1 flash drive plugged into a USB 3.1 port. The speeds are maxing out at 35 MB/s.

Using USBTreeView I get the following:

USBTreeView

It's running on an AMD USB 3.10 host and the port is showing an S.

However, if I look at Connection Information I get the following:

---------------- Connection Information ---------------
Connection Index         : 0x08 (8)
Connection Status        : 0x01 (DeviceConnected)
Current Config Value     : 0x01
Device Address           : 0x6A (106)
Is Hub                   : 0x00 (no)
Device Bus Speed         : 0x02 (High-Speed) -> not true, see below in Connection Information V2
Number Of Open Pipes     : 0x02 (2 pipes to data endpoints)
Pipe[0]                  : EndpointID=1  Direction=OUT  ScheduleOffset=0  Type=Bulk
Pipe[1]                  : EndpointID=2  Direction=IN   ScheduleOffset=0  Type=Bulk
Data (HexDump)           : 08 00 00 00 12 01 10 03 00 00 00 09 0C 09 00 10   ................
                           00 11 01 02 03 01 01 02 00 6A 00 02 00 00 00 01   .........j......
                           00 00 00 07 05 01 02 00 04 00 00 00 00 00 07 05   ................
                           82 02 00 04 00 00 00 00 00

Note under "Device Bus Speed" it says USB 2.0 and "not true, see below in Connection Information V2"

Under Connection Information V2 I have:

--------------- Connection Information V2 -------------
Connection Index         : 0x08 (8)
Length                   : 0x10 (16 bytes)
SupportedUsbProtocols    : 0x04
 Usb110                  : 0 (no)
 Usb200                  : 0 (no)
 Usb300                  : 1 (yes)
 ReservedMBZ             : 0x00
Flags                    : 0x03
 DevIsOpAtSsOrHigher     : 1 (Is operating at SuperSpeed or higher)
 DevIsSsCapOrHigher      : 1 (Is SuperSpeed capable or higher)
 DevIsOpAtSsPlusOrHigher : 0 (Is not operating at SuperSpeedPlus or higher)
 DevIsSsPlusCapOrHigher  : 0 (Is not SuperSpeedPlus capable or higher)
 ReservedMBZ             : 0x00
Data (HexDump)           : 08 00 00 00 10 00 00 00 04 00 00 00 03 00 00 00   ................

Here it's clear than USB 3.0 should be supported.

I get the same issue on my USB 3.0 ports as on the USB 3.1 port and with other USB flash drives.

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7
  • USB3 involves both a "standard" USB connection along with additional pins with up to 4 lanes of super-speed PCIe style connections. the "old" USB connection may only be needed to negotiate and set up the other connections and USB2 "high speed" may not be needed or even used during standard operation. Your data seems to suggest you are operating at superspeed, which is expected, but high speed USB2 may be ignored.
    – Mokubai ♦
    Commented Oct 28, 2020 at 15:51
  • I should have said I'm definitely not operating at SS. My speeds are maxing out at 35 MB/s.
    – Turkeyphant
    Commented Oct 28, 2020 at 16:39
  • Reading or writing? Writing may be subject to caveats such as "up to" speeds which are only obtainable on a pristine device in laboratory conditions and after the device has been left powered for some unknown length of time for it to have done it's own housekeeping, wear levelling and block erasure. Copying from the device should be faster, but again "up to" caveats usually apply. Just because it claims to be USB3.1 doesn't mean it is any faster than an older device, just that the interface is faster. It could have some very old flash memory fitted.
    – Mokubai ♦
    Commented Oct 28, 2020 at 16:44
  • Most USB flash memories say "up to 110MB/s!!!!! * " in big flashy marketing speak and have a nice caveat " * Read speeds in laboratory conditions" and completely ignore or refuse to mention write speeds, the awful write latency, or the even worse IOPs that make the drive hardly any better than a slow MicroSD card. If the device is an M.2 PCIe SSD in a USB3.1 enclosure then I would expect good speeds, but even then there are caveats in the form of a write-through cache that means that only the 1st GB or two of writes will be "fast" and the rest fall back to slower speeds.
    – Mokubai ♦
    Commented Oct 28, 2020 at 16:51
  • This is a brand new Samsung BAR Plus 64 GB USB 3.1 (MUF-64BE4). I understand that the write speeds could be slower that USB 3.1 theoretical limits but 35 MB/s is USB 2.0 speeds and taking the piss a bit.
    – Turkeyphant
    Commented Oct 28, 2020 at 17:11

1 Answer 1

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1

This is not a problem with your USB or the device, which is reporting that you are indeed using a Superspeed connection. It is a design feature of USB flash drives.

USB 3.0 flash drives generally display fast read speeds only. Write speeds tend to be comparatively slow, sometimes to the point of being slower than older USB standards. They often hide or otherwise do not clearly mention or define write speeds.

From the Amazon page for the Samsung MUF-64BE4 they list the following regarding speed, and is repeated several times in the body of the page:

Fast and convenient read speeds up to 300 MB/s

and at only one point in the header do they mention, in rather less prominent fashion

Write Speed 30

but never again in the body of the page and specifications.

On top of that write speeds are often a factor of the size of the device. Larger devices tend to be constructed from a multiple of smaller memory block devices and as such a 128GB device might have close to twice the write speed of a 64GB device and so on.

The reviews section does indeed paint a picture of a device with fast read speeds, but disappointingly slow write speeds, with the 64GB version being somewhere around 30-35MB/s, the 128GB being around 60MB/s, and the 256GB being around 80MB/s write speeds.

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2
  • Thanks for a good answer. I guess there could be more clarity as to what 0x02 (High-Speed) -> not true means.
    – Turkeyphant
    Commented Oct 28, 2020 at 22:03
  • Indeed, under your v2 block it even states that the device does not support USB1.1 or USB2 and only supports 3. Then you have superspeed capable and enabled flags. It looks like everything is what you would expect to see. Everything looks right except for the speed itself which points at simply being slow flash memory.
    – Mokubai ♦
    Commented Oct 28, 2020 at 23:16

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