Ultra Flair 64GB USB 3.0 very slow write speeds

Hello, I just bought an Sandisk Ultra Flair usb 3.0 drive, the 64gb version. The write speeds to the drive are EXTREMELY slow for a USB 3.0 drive. I plugged it into a USB 3.0 port and copying about ~18gb of files to it, first of all it started at about 30 MBps instead of 60MBps and after transferring some files the speed dropped down significantly to an average of about 10 MBps, which is much slower than any of my other brand USB 2.0 drives. Both large files and small files transfer very slowly. I also have a Sandisk Ultra 256GB USB 3.0 drive and that one as well is slower than my other brand USB 2.0 drives. If this is intended operation I am very disappointed in Sandisk’s false advertising “15 times faster than USB 2.0” which this drive was advertised as. Are there any fixes which can make the write speeds faster?

Are you using it on the same machine as before?  Are you running the same OS as before?  Are you running the same AV as before?  And the same malware apps as before?  Is the OS downloading updates as you write to the USB drive?  These things impact speed also.  SanDisk’s stats are on a machine doing nothing other than reading and writing to the USB drive.

Try running your machine in safe mode and see if the speed improves.

I have an Ultra Flair 128GB that does the same thing, except if ran even longer (before it locks up), as it runs it gets slow and slower, it dips down to about 6MB/s when there is a high # of writes, but sustained writing of larger files does average about 8MB to 10MB/s.

-  The OS is not updating.  That is disabled and done manually.

-  AV enabled or disabled makes no difference

-  Malware apps not running but system scanned and confirmed clean

-  Same behavior on rear port, front port, USB hub, and different system

In all cases removing the Ultra Flair and using a Sandisk Extreme USB3 instead, works fine without this slowdown.

It is slowing down as it gets hot and if left running hot it eventually locks up and can’t be accessed until removed, allowed to cool, then plugged back in.   The only time it can achieve over 12MB/s is if it was sitting unused, then plugged in and a copy started before it warms up, and then only until it warms up, a minute or two at most.

I never expected 15 times faster than USB2 for writes, but I did expect it to be faster continuous writes than my 8+ year old USB2 flash drives which have dozens of times as many writes to them already.

This was all observed using the factory format.  At one point I had nearly filled it and wanted reuse it for something else and found it was impossible to delete all the files in a timely manner because it kept locking up from heat, so I then reformatted it as FAT32.  That made minimal to no difference, still slows down to similar sub-10MB/s speeds after a minute or two.

I have the same problems.Sometimes it gots hot and the writing rate goes down to 4000k Bit/sec (even it is not hot).It stops an wait for a while.then a little (or more) data transfer and it stops again. 

I just bought an Ultra Flair 128 GB.  I see slow downs too, but not as bad as others.  I have tried several times with different formatting.  What I see is that for the first 2 GB of transfer, it writes at 70 MB/s.  after the first 2 GB, the write speed slows down to about 30 MB/s +/- 3 MB/s with no further slowing.

I am disappointed with this very reproducible slow down.  I am a long time satisfied SanDIsk customer going back over a decade with many SD cards and CF cards.  I chose this USB drive because of my past positive experience with SanDisk products.  So I am quite disappointed with the slow down and this thread has no plausible fix.

Do you have it configured in Windows for Safe Removal?  I believe that prevents buffering which slows things down.

Hi, I’m in the same boat.

This usb key should be called _ Ultra Sad _ writing speed.  :frowning:

I have the same problem with one Sandisk USB Cruzer Force 16GB stick, (2.0 ? or 3.0 ?) TEST SPEED using USB Flash Bench are.

Refreshing devices.
Refreshing devices. [Done]
Starting benchmark.
Bechmarking E:(4C531001350502122555)
Started at 7/23/2019 5:26:34 PM
Filename: E:\test.tmp
Starting large file benchmark. With 100MB file.
16384k:6 Write Speed:5.54MB/s
16384k:6 Write Speed:5.84MB/s
16384k:6 Write Speed:5.67MB/s
16384k:6 Average Write Speed:5.68MB/s
16384k:6 Read Speed:26.56MB/s
16384k:6 Read Speed:26.63MB/s
16384k:6 Read Speed:26.70MB/s
16384k:6 Average Read Speed:26.63MB/s
8192k:12 Write Speed:5.30MB/s
8192k:12 Write Speed:5.72MB/s
8192k:12 Write Speed:5.96MB/s
8192k:12 Average Write Speed:5.65MB/s
8192k:12 Read Speed:26.52MB/s
8192k:12 Read Speed:26.62MB/s
8192k:12 Read Speed:26.69MB/s
8192k:12 Average Read Speed:26.61MB/s
4096k:25 Write Speed:5.86MB/s
4096k:25 Write Speed:5.60MB/s
4096k:25 Write Speed:5.98MB/s
4096k:25 Average Write Speed:5.81MB/s
4096k:25 Read Speed:26.32MB/s
4096k:25 Read Speed:26.85MB/s
4096k:25 Read Speed:26.70MB/s
4096k:25 Average Read Speed:26.62MB/s
2048k:50 Write Speed:5.74MB/s
2048k:50 Write Speed:6.41MB/s
2048k:50 Write Speed:5.09MB/s
2048k:50 Average Write Speed:5.70MB/s
2048k:50 Read Speed:26.59MB/s
2048k:50 Read Speed:26.73MB/s
2048k:50 Read Speed:26.66MB/s
2048k:50 Average Read Speed:26.66MB/s
1024k:100 Write Speed:6.42MB/s
1024k:100 Write Speed:5.58MB/s
1024k:100 Write Speed:6.05MB/s
1024k:100 Average Write Speed:6.00MB/s
1024k:100 Read Speed:26.43MB/s
1024k:100 Read Speed:26.60MB/s
1024k:100 Read Speed:26.67MB/s
1024k:100 Average Read Speed:26.57MB/s
512k:200 Write Speed:5.62MB/s
512k:200 Write Speed:5.47MB/s
512k:200 Write Speed:6.28MB/s
512k:200 Average Write Speed:5.77MB/s
512k:200 Read Speed:26.64MB/s
512k:200 Read Speed:26.55MB/s
512k:200 Read Speed:26.59MB/s
512k:200 Average Read Speed:26.59MB/s
Deleting file.
Starting small file benchmark. With 10MB file.
256k:40 Write Speed:11.23MB/s
256k:40 Write Speed:11.17MB/s
256k:40 Write Speed:3.78MB/s
256k:40 Average Write Speed:6.77MB/s
256k:40 Read Speed:25.19MB/s
256k:40 Read Speed:24.39MB/s
256k:40 Read Speed:25.46MB/s
256k:40 Average Read Speed:25.01MB/s
128k:80 Write Speed:8.59MB/s
128k:80 Write Speed:10.24MB/s
128k:80 Write Speed:10.23MB/s
128k:80 Average Write Speed:9.62MB/s
128k:80 Read Speed:25.03MB/s
128k:80 Read Speed:25.26MB/s
128k:80 Read Speed:25.30MB/s
128k:80 Average Read Speed:25.20MB/s
64k:160 Write Speed:7.66MB/s
64k:160 Write Speed:10.97MB/s
64k:160 Write Speed:10.58MB/s
64k:160 Average Write Speed:9.49MB/s
64k:160 Read Speed:24.50MB/s
64k:160 Read Speed:24.23MB/s
64k:160 Read Speed:24.46MB/s
64k:160 Average Read Speed:24.40MB/s
32k:320 Write Speed:6.47MB/s
32k:320 Write Speed:6.45MB/s
32k:320 Write Speed:5.95MB/s
32k:320 Average Write Speed:6.28MB/s
32k:320 Read Speed:23.19MB/s
32k:320 Read Speed:23.27MB/s
32k:320 Read Speed:23.05MB/s
32k:320 Average Read Speed:23.17MB/s
Deleting file.
Starting tiny file benchmark. With 1MB file.
16k:320 Write Speed:3.72MB/s
16k:320 Write Speed:5.03MB/s
16k:320 Write Speed:2.57MB/s
16k:320 Average Write Speed:3.50MB/s
16k:320 Read Speed:20.28MB/s
16k:320 Read Speed:19.99MB/s
16k:320 Read Speed:19.91MB/s
16k:320 Average Read Speed:20.06MB/s
8k:640 Write Speed:2.69MB/s
8k:640 Write Speed:2.42MB/s
8k:640 Write Speed:2.42MB/s
8k:640 Average Write Speed:2.50MB/s
8k:640 Read Speed:13.99MB/s
8k:640 Read Speed:13.89MB/s
8k:640 Read Speed:13.79MB/s
8k:640 Average Read Speed:13.89MB/s
4k:1280 Write Speed:1.49MB/s
4k:1280 Write Speed:1.44MB/s
4k:1280 Write Speed:1.15MB/s
4k:1280 Average Write Speed:1.34MB/s
4k:1280 Read Speed:9.77MB/s
4k:1280 Read Speed:9.70MB/s
4k:1280 Read Speed:9.54MB/s
4k:1280 Average Read Speed:9.67MB/s
2k:2560 Write Speed:0.90MB/s
2k:2560 Write Speed:0.87MB/s
2k:2560 Write Speed:0.90MB/s
2k:2560 Average Write Speed:0.89MB/s
2k:2560 Read Speed:6.35MB/s
2k:2560 Read Speed:6.25MB/s
2k:2560 Read Speed:6.32MB/s
2k:2560 Average Read Speed:6.30MB/s
1k:5120 Write Speed:0.50MB/s
1k:5120 Write Speed:0.47MB/s
Requesting stop…
1k:5120 Write Speed:0.49MB/s
1k:5120 Average Write Speed:0.49MB/s

I have also a Sandisk Ultra Fit USB 3.0 16GB stick inserted in the same USB from my laptout but the speeds are
total different.

Refreshing devices.
Refreshing devices. [Done]
Starting benchmark.
Bechmarking E:(4C531001481116113330)
Started at 7/23/2019 5:40:02 PM
Filename: E:\test.tmp
Starting large file benchmark. With 100MB file.
16384k:6 Write Speed:95.16MB/s
16384k:6 Write Speed:94.96MB/s
16384k:6 Write Speed:94.94MB/s
16384k:6 Average Write Speed:95.02MB/s
16384k:6 Read Speed:133.22MB/s
16384k:6 Read Speed:133.21MB/s
16384k:6 Read Speed:133.09MB/s
16384k:6 Average Read Speed:133.17MB/s
8192k:12 Write Speed:94.92MB/s
8192k:12 Write Speed:94.85MB/s
8192k:12 Write Speed:94.86MB/s
8192k:12 Average Write Speed:94.88MB/s
8192k:12 Read Speed:133.61MB/s
8192k:12 Read Speed:133.58MB/s
8192k:12 Read Speed:133.52MB/s
8192k:12 Average Read Speed:133.57MB/s
4096k:25 Write Speed:94.97MB/s
4096k:25 Write Speed:94.97MB/s
4096k:25 Write Speed:95.06MB/s
4096k:25 Average Write Speed:95.00MB/s
4096k:25 Read Speed:134.28MB/s
4096k:25 Read Speed:134.23MB/s
4096k:25 Read Speed:134.21MB/s
4096k:25 Average Read Speed:134.24MB/s
2048k:50 Write Speed:95.01MB/s
2048k:50 Write Speed:94.57MB/s
2048k:50 Write Speed:94.95MB/s
2048k:50 Average Write Speed:94.84MB/s
2048k:50 Read Speed:134.41MB/s
2048k:50 Read Speed:134.07MB/s
2048k:50 Read Speed:134.32MB/s
2048k:50 Average Read Speed:134.27MB/s
1024k:100 Write Speed:94.48MB/s
1024k:100 Write Speed:94.17MB/s
1024k:100 Write Speed:93.88MB/s
1024k:100 Average Write Speed:94.17MB/s
1024k:100 Read Speed:134.12MB/s
1024k:100 Read Speed:133.90MB/s
1024k:100 Read Speed:133.98MB/s
1024k:100 Average Read Speed:134.00MB/s
512k:200 Write Speed:92.87MB/s
512k:200 Write Speed:92.72MB/s
512k:200 Write Speed:93.09MB/s
512k:200 Average Write Speed:92.90MB/s
512k:200 Read Speed:133.94MB/s
512k:200 Read Speed:130.88MB/s
512k:200 Read Speed:133.79MB/s
512k:200 Average Read Speed:132.85MB/s
Deleting file.
Starting small file benchmark. With 10MB file.
256k:40 Write Speed:66.27MB/s
256k:40 Write Speed:78.85MB/s
256k:40 Write Speed:78.64MB/s
256k:40 Average Write Speed:74.09MB/s
256k:40 Read Speed:122.65MB/s
256k:40 Read Speed:120.92MB/s
256k:40 Read Speed:120.73MB/s
256k:40 Average Read Speed:121.42MB/s
128k:80 Write Speed:61.05MB/s
128k:80 Write Speed:60.48MB/s
128k:80 Write Speed:60.54MB/s
128k:80 Average Write Speed:60.69MB/s
128k:80 Read Speed:108.94MB/s
128k:80 Read Speed:107.78MB/s
128k:80 Read Speed:106.74MB/s
128k:80 Average Read Speed:107.81MB/s
64k:160 Write Speed:41.49MB/s
64k:160 Write Speed:34.13MB/s
64k:160 Write Speed:32.67MB/s
64k:160 Average Write Speed:35.71MB/s
64k:160 Read Speed:101.30MB/s
64k:160 Read Speed:103.64MB/s
64k:160 Read Speed:103.52MB/s
64k:160 Average Read Speed:102.81MB/s
32k:320 Write Speed:26.77MB/s
32k:320 Write Speed:23.85MB/s
32k:320 Write Speed:26.73MB/s
32k:320 Average Write Speed:25.71MB/s
32k:320 Read Speed:73.27MB/s
32k:320 Read Speed:73.40MB/s
32k:320 Read Speed:73.35MB/s
32k:320 Average Read Speed:73.34MB/s
Deleting file.
Starting tiny file benchmark. With 1MB file.
16k:320 Write Speed:15.22MB/s
16k:320 Write Speed:15.25MB/s
16k:320 Write Speed:13.26MB/s
16k:320 Average Write Speed:14.51MB/s
16k:320 Read Speed:50.86MB/s
16k:320 Read Speed:50.61MB/s
16k:320 Read Speed:50.38MB/s
16k:320 Average Read Speed:50.62MB/s
8k:640 Write Speed:7.10MB/s
8k:640 Write Speed:7.50MB/s
8k:640 Write Speed:7.92MB/s
8k:640 Average Write Speed:7.49MB/s
8k:640 Read Speed:31.20MB/s
8k:640 Read Speed:30.87MB/s
8k:640 Read Speed:30.99MB/s
8k:640 Average Read Speed:31.02MB/s
4k:1280 Write Speed:2.33MB/s
4k:1280 Write Speed:2.29MB/s
4k:1280 Write Speed:2.28MB/s
4k:1280 Average Write Speed:2.30MB/s
4k:1280 Read Speed:17.44MB/s
4k:1280 Read Speed:17.47MB/s
4k:1280 Read Speed:17.05MB/s
4k:1280 Average Read Speed:17.32MB/s
2k:2560 Write Speed:1.18MB/s
2k:2560 Write Speed:1.18MB/s
2k:2560 Write Speed:1.19MB/s
2k:2560 Average Write Speed:1.18MB/s
2k:2560 Read Speed:9.29MB/s
2k:2560 Read Speed:9.31MB/s
2k:2560 Read Speed:9.33MB/s
2k:2560 Average Read Speed:9.31MB/s
1k:5120 Write Speed:0.59MB/s
1k:5120 Write Speed:0.60MB/s
1k:5120 Write Speed:0.60MB/s
1k:5120 Average Write Speed:0.60MB/s
1k:5120 Read Speed:4.81MB/s
1k:5120 Read Speed:4.86MB/s
1k:5120 Read Speed:4.86MB/s
1k:5120 Average Read Speed:4.84MB/s
Deleting file.
Benchmark done.
Ended at 7/23/2019 5:43:07 PM

  • Chipset drivers are update
  • The option in the device manager The Better performance is marked in both USBs

Why I get slow speed transfer from one and in the other is perfect. Sandisk you should create a tool to fix or test a USB performance and what could be the issue with the slow transfers.

Same problem with 2 ultra 128 and 256 over 5 hours to transfer 160g. Hp590 i7 windows10, checked in device manager driver is dated2006 Microsoft, when device plugged in, could this be the problem. All other usb 3 drivers Microsoft 2020. Except when device unplugged usb composite is 2006 too