Writing to my USB 3 thumb drive (SanDisk Extreme SDCZ80-064G-FFP) is very slow on Linux: 1 GB takes longer than 200s. Using Windows (dual-boot on the same computer), the same 1 GB file can be copied in about 8s. The stick is formatted in FAT (it came pre-preformatted and I didn't change it) and I would like to keep it this way since I am using it on Windows as well,How can I fix it? What steps can I perform to diagnose what is causing this?I am running Manjaro/Arch with kernel version 4.5.4-1.Edit:First of all: I realized that the drive is formatted in FAT (not in NTFS, as I originally stated in the question) when I tried to mount it with -o big_writes. Sorry for the mistake!I am adding the outputs of the commands mentioned in the comments. I don't see a problem with any of these.Output of journalctl -f when I connect the drive, mount it and write some data:Mai 23 20:32:37 manjaro kernel: usb 2-6: USB disconnect, device number 7Mai 23 20:32:39 manjaro dbus[608]: [system] Activating via systemd: service name='org.freedesktop.Avahi' unit='dbus-org.freedesktop.Avahi.service'Mai 23 20:32:39 manjaro dbus[608]: [system] Activation via systemd failed for unit 'dbus-org.freedesktop.Avahi.service': Unit dbus-org.freedesktop.Avahi.service not found.Mai 23 20:32:41 manjaro kernel: usb 2-6: new SuperSpeed USB device number 8 using xhci_hcdMai 23 20:32:41 manjaro kernel: usb-storage 2-6:1.0: USB Mass Storage device detectedMai 23 20:32:41 manjaro kernel: scsi host12: usb-storage 2-6:1.0Mai 23 20:32:41 manjaro mtp-probe[3627]: checking bus 2, device 8: /sys/devices/pci0000:00/0000:00:14.0/usb2/2-6Mai 23 20:32:41 manjaro mtp-probe[3627]: bus: 2, device: 8 was not an MTP deviceMai 23 20:32:42 manjaro kernel: scsi 12:0:0:0: Direct-Access     SanDisk  Extreme          0001 PQ: 0 ANSI: 6Mai 23 20:32:42 manjaro kernel: sd 12:0:0:0: [sdc] 122544516 512-byte logical blocks: (62.7 GB/58.4 GiB)Mai 23 20:32:42 manjaro kernel: sd 12:0:0:0: [sdc] Write Protect is offMai 23 20:32:42 manjaro kernel: sd 12:0:0:0: [sdc] Mode Sense: 53 00 00 08Mai 23 20:32:42 manjaro kernel: sd 12:0:0:0: [sdc] Write cache: disabled, read cache: enabled, doesn't support DPO or FUAMai 23 20:32:42 manjaro kernel:  sdc: sdc1Mai 23 20:32:42 manjaro kernel: sd 12:0:0:0: [sdc] Attached SCSI removable diskMai 23 20:32:43 manjaro dbus[608]: [system] Activating via systemd: service name='org.freedesktop.Avahi' unit='dbus-org.freedesktop.Avahi.service'Mai 23 20:32:43 manjaro dbus[608]: [system] Activation via systemd failed for unit 'dbus-org.freedesktop.Avahi.service': Unit dbus-org.freedesktop.Avahi.service not found.Mai 23 20:32:52 manjaro sudo[3667]: user : TTY=pts/1 ; PWD=/home/user ; USER=root ; COMMAND=/usr/bin/mount /dev/sdc1 /mnt/Mai 23 20:32:52 manjaro sudo[3667]: pam_unix(sudo:session): session opened for user root by (uid=0)Mai 23 20:32:52 manjaro sudo[3667]: pam_unix(sudo:session): session closed for user rootMai 23 20:33:11 manjaro sudo[3676]: user : TTY=pts/1 ; PWD=/home/user ; USER=root ; COMMAND=/usr/bin/dd bs=1M count=1024 if=/dev/zero of=/mnt/test conv=fdatasync status=progressMai 23 20:33:11 manjaro sudo[3676]: pam_unix(sudo:session): session opened for user root by (uid=0)Mai 23 20:35:01 manjaro anacron[2235]: Job `cron.daily' startedMai 23 20:35:03 manjaro anacron[2235]: Job `cron.daily' terminatedMai 23 20:35:45 manjaro sudo[3676]: pam_unix(sudo:session): session closed for user rootOuput of dmesg:[ 2507.302345] usb 2-6: new SuperSpeed USB device number 8 using xhci_hcd[ 2507.317395] usb-storage 2-6:1.0: USB Mass Storage device detected[ 2507.317758] scsi host12: usb-storage 2-6:1.0[ 2508.319922] scsi 12:0:0:0: Direct-Access     SanDisk  Extreme          0001 PQ: 0 ANSI: 6[ 2508.333123] sd 12:0:0:0: [sdc] 122544516 512-byte logical blocks: (62.7 GB/58.4 GiB)[ 2508.333353] sd 12:0:0:0: [sdc] Write Protect is off[ 2508.333362] sd 12:0:0:0: [sdc] Mode Sense: 53 00 00 08[ 2508.333634] sd 12:0:0:0: [sdc] Write cache: disabled, read cache: enabled, doesn't support DPO or FUA[ 2508.346488]  sdc: sdc1[ 2508.347918] sd 12:0:0:0: [sdc] Attached SCSI removable diskCommands used for mounting and writing:$ sudo mount /dev/sdc1 /mnt/$ sudo dd bs=1M count=1024 if=/dev/zero of=/mnt/test conv=fdatasync status=progress1024+0 records in1024+0 records out1073741824 bytes (1,1 GB, 1,0 GiB) copied, 154,158 s, 7,0 MB/sOutput of lsusb -t:/:  Bus 04.Port 1: Dev 1, Class=root_hub, Driver=xhci_hcd/2p, 5000M/:  Bus 03.Port 1: Dev 1, Class=root_hub, Driver=xhci_hcd/2p, 480M/:  Bus 02.Port 1: Dev 1, Class=root_hub, Driver=xhci_hcd/10p, 5000M    |__ Port 6: Dev 8, If 0, Class=Mass Storage, Driver=usb-storage, 5000M/:  Bus 01.Port 1: Dev 1, Class=root_hub, Driver=xhci_hcd/16p, 480M    |__ Port 9: Dev 2, If 0, Class=Human Interface Device, Driver=usbhid, 1.5M    |__ Port 10: Dev 3, If 0, Class=Human Interface Device, Driver=usbhid, 1.5M    |__ Port 10: Dev 3, If 1, Class=Human Interface Device, Driver=usbhid, 1.5MEdit 2: I tried two other kernels: 4.4.11 and 4.6.0. Writing is still slow with both of them. Additionally, the problem seems to be related to the drive since I get higher transfer speeds (90 MB/s) for an external USB 3 hard disk.Edit 3: I did some benchmarking on an Ubuntu 16.04 Live System. The results are way better (though still not very good):ubuntu@ubuntu:/media/ubuntu/274D-D62C$ dd bs=1M count=1024 if=/dev/zero of=./test conv=fdatasync status=progress1024+0 records in1024+0 records out1073741824 bytes (1.1 GB, 1.0 GiB) copied, 12.2623 s, 87.6 MB/subuntu@ubuntu:/media/ubuntu/274D-D62C$ dd bs=1M count=1024 if=/dev/zero of=./test conv=fdatasync status=progress1024+0 records in1024+0 records out1073741824 bytes (1.1 GB, 1.0 GiB) copied, 64.5742 s, 16.6 MB/subuntu@ubuntu:/media/ubuntu/274D-D62C$ dd bs=1M count=1024 if=/dev/zero of=./test conv=fdatasync status=progress1024+0 records in1024+0 records out1073741824 bytes (1.1 GB, 1.0 GiB) copied, 83.6521 s, 12.8 MB/subuntu@ubuntu:/media/ubuntu/274D-D62C$ dd bs=1M count=1024 if=/dev/zero of=./test conv=fdatasync status=progress1024+0 records in1024+0 records out1073741824 bytes (1.1 GB, 1.0 GiB) copied, 21.842 s, 49.2 MB/subuntu@ubuntu:/media/ubuntu/274D-D62C$ dd bs=1M count=1024 if=/dev/zero of=./test conv=fdatasync status=progress1024+0 records in1024+0 records out1073741824 bytes (1.1 GB, 1.0 GiB) copied, 16.3149 s, 65.8 MB/sEdit 4: I just tried it once more using a recent Arch/Manjaro kernel (4.11.1) and the result is a bit better: I get transfer speeds of about 10 MB/s (so ~100s for 1GB). This is, however, still much slower than Windows.
Slow USB 3 write speed
performance;usb drive;io