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TLDR: How do I troubleshoot a slow usb 3.1 device plugged into a laptop.

ISSUE: When I copy (tried GUI and terminal) the first few .iso files copy almost instantly 300mb/s+, but then the 3rd/4th start to slow to below 12mb/s (even if copying one at a time).

HARDWARE:

  • Dell XPS 15 9520 (Fedora Linux 37 - Workstation)
  • Sandisk Extreme GO USB 3.1 64GB (using Ventoy)
  • Dell USB-C to USB-A/HDMI Adapter
  • Anker PowerExpand+ 7-in-1 USB-C PD Hub

TRIED:

  • Reformatting usb (gparted - exfat).
  • Using USB with and without Ventoy installed.
  • Using different ports, different adapters/hubs.
  • Copying lots of .iso files in one go vs copying one file at a time - waiting until each file fully copied.

Either way after a few files (around 4GB) the USB drive becomes very slow. Ejecting the USB (via GUI or terminal) can take a long time but after remounting fast speeds return. When ejecting using GUI I get message device busy - so now use terminal and wait until command has completed.

DRIVER | PORT DETAILS:

$ udevadm info -q path -n /dev/sdc /devices/pci0000:00/0000:00:14.0/usb4/4-1/4-1.1/4-1.1:1.0/host1/target1:0:0/1:0:0:0/block/sdc $ lsusb -t /: Bus 04.Port 1: Dev 1, Class=root_hub, Driver=xhci_hcd/4p, 10000M |__ Port 1: Dev 2, If 0, Class=Hub, Driver=hub/1p, 5000M |__ Port 1: Dev 3, If 0, Class=Mass Storage, Driver=usb-storage, 5000M /: Bus 03.Port 1: Dev 1, Class=root_hub, Driver=xhci_hcd/12p, 480M |__ Port 1: Dev 2, If 0, Class=Hub, Driver=hub/5p, 480M |__ Port 5: Dev 6, If 0, Class=, Driver=, 480M |__ Port 2: Dev 3, If 0, Class=Hub, Driver=hub/4p, 480M |__ Port 1: Dev 5, If 0, Class=Hub, Driver=hub/4p, 480M |__ Port 1: Dev 9, If 0, Class=Human Interface Device, Driver=usbhid, 12M |__ Port 4: Dev 8, If 0, Class=Hub, Driver=hub/4p, 480M |__ Port 3: Dev 11, If 0, Class=Human Interface Device, Driver=usbhid, 1.5M |__ Port 3: Dev 11, If 1, Class=Human Interface Device, Driver=usbhid, 1.5M |__ Port 4: Dev 12, If 0, Class=Hub, Driver=hub/4p, 480M |__ Port 4: Dev 13, If 0, Class=Hub, Driver=hub/4p, 480M |__ Port 3: Dev 15, If 0, Class=Hub, Driver=hub/4p, 480M |__ Port 2: Dev 16, If 0, Class=, Driver=, 12M |__ Port 6: Dev 4, If 0, Class=Video, Driver=uvcvideo, 480M |__ Port 6: Dev 4, If 1, Class=Video, Driver=uvcvideo, 480M |__ Port 6: Dev 4, If 2, Class=Video, Driver=uvcvideo, 480M |__ Port 6: Dev 4, If 3, Class=Video, Driver=uvcvideo, 480M |__ Port 9: Dev 7, If 0, Class=Vendor Specific Class, Driver=, 12M |__ Port 10: Dev 10, If 0, Class=Wireless, Driver=btusb, 12M |__ Port 10: Dev 10, If 1, Class=Wireless, Driver=btusb, 12M /: Bus 02.Port 1: Dev 1, Class=root_hub, Driver=xhci_hcd/2p, 20000M/x2 |__ Port 1: Dev 2, If 0, Class=Hub, Driver=hub/4p, 5000M |__ Port 2: Dev 3, If 0, Class=Vendor Specific Class, Driver=r8152, 5000M |__ Port 3: Dev 4, If 0, Class=Mass Storage, Driver=usb-storage, 5000M /: Bus 01.Port 1: Dev 1, Class=root_hub, Driver=xhci_hcd/1p, 480M
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  • There's nothing software can do here. Your drive is plain slow. Commented Apr 10, 2023 at 12:26
  • This specific drive or USB 3.1 flash drives in general? Is it possible to achieve fast sustained transfer speeds using USB 3.1 flash drives or will I need to use something like a M.2 NVME in external case? Commented Apr 10, 2023 at 12:34
  • this one, specifically. Though it's doing OK-ish for a USB stick, it's not fast. Commented Apr 10, 2023 at 12:36
  • Could you recomend a fast usb flash drive for me please. I'm not sure how to identify a fast one from a slow one. Commented Apr 10, 2023 at 12:43
  • 1
    I’m voting to close this question because it's unrelated to the topic of this site: Slow hardware is slow hardware. Commented Apr 10, 2023 at 13:32

1 Answer 1

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Detailed reasons for why speeds slow down when copying are discussed in this post (e.g. memory cache). Anecdotally, for me the temperature of the device also seemed to play a part.

This website was useful for setting realistic expectations on what to expect from usb drive devices.

This guide shows how to use hdparm and dd to benchmark drive speeds

Tests:

$ hdparm -tT /dev/sde /dev/sde: Timing cached reads: 36072 MB in 2.00 seconds = 18064.09 MB/sec Timing buffered disk reads: 554 MB in 3.00 seconds = 184.65 MB/sec

Small amount of data:

$ dd if=/dev/zero of=./largefile bs=8k count=10000 10000+0 records in 10000+0 records out 81920000 bytes (82 MB, 78 MiB) copied, 0.0478257 s, 1.7 GB/s $ dd if=./largefile of=/dev/null bs=8k 10000+0 records in 10000+0 records out 81920000 bytes (82 MB, 78 MiB) copied, 0.473879 s, 173 MB/s

Larger amount of data

$ dd if=/dev/zero of=./largefile bs=8k count=1000000 1000000+0 records in 1000000+0 records out 8192000000 bytes (8.2 GB, 7.6 GiB) copied, 658.022 s, 12.4 MB/s $ dd if=./largefile of=/dev/null bs=8k 1000000+0 records in 1000000+0 records out 8192000000 bytes (8.2 GB, 7.6 GiB) copied, 45.1854 s, 181 MB/s

Results/conclusion: Compared slightly faster than the average speed posted on usb.userbenchmark.com and it is nice to now know whats to be expected and a way to test it.

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  • These tests are pretty meaningless, as you might be caching gigabytes of write data in RAM Commented Apr 24, 2023 at 23:02

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