Samsung USB immediate speed drop during test

[Kisianik]

Hi

This is the first time I see this happened. Drive in question is Samsung 64GB BAR (METAL) USB 3.0 Flash Drive (MUF-64BA/AM). Previously I tested and returned (for the same reason) Samsung 64GB USB 3.0 Flash Drive Duo (MUF-64CB/AM). So 2 different models are showing the same behavior.

Tested with CrystalDisk. Drive came from the store formatted as FAT 32, so I reformatted to ExFat prior to testing.

CrystalDiskMark 5.2.1 x64 (C) 2007-2017
Sequential Read (Q= 32,T= 1) : 151.502 MB/s
Sequential Write (Q= 32,T= 1) : 38.245 MB/s
Random Read 4KiB (Q= 32,T= 1) : 5.064 MB/s [ 1236.3 IOPS]
Random Write 4KiB (Q= 32,T= 1) : 1.288 MB/s [ 314.5 IOPS]
Sequential Read (T= 1) : 158.546 MB/s
Sequential Write (T= 1) : 52.004 MB/s
Random Read 4KiB (Q= 1,T= 1) : 5.029 MB/s [ 1227.8 IOPS]
Random Write 4KiB (Q= 1,T= 1) : 1.646 MB/s [ 401.9 IOPS]

Test : 1024 MiB [H: 0.0% (0.0/59.8 GiB)] (x1) [Interval=5 sec]

CrystalDiskMark 5.2.1 x64 (C) 2007-2017 hiyohiyo
Sequential Read (Q= 32,T= 1) : 140.828 MB/s
Sequential Write (Q= 32,T= 1) : 110.309 MB/s
Random Read 4KiB (Q= 32,T= 1) : 4.495 MB/s [ 1097.4 IOPS]
Random Write 4KiB (Q= 32,T= 1) : 0.850 MB/s [ 207.5 IOPS]
Sequential Read (T= 1) : 146.588 MB/s
Sequential Write (T= 1) : 116.394 MB/s
Random Read 4KiB (Q= 1,T= 1) : 4.494 MB/s [ 1097.2 IOPS]
Random Write 4KiB (Q= 1,T= 1) : 0.958 MB/s [ 233.9 IOPS]

Test : 100 MiB [H: 0.0% (0.0/59.8 GiB)] (x1) [Interval=5 sec]

Looks very good. Next I removed the drive from PC and reinserted. Same tests again... SURPRISE.

CrystalDiskMark 5.2.1 x64 (C) 2007-2017 hiyohiyo
Sequential Read (Q= 32,T= 1) : 40.897 MB/s
Sequential Write (Q= 32,T= 1) : 41.053 MB/s
Random Read 4KiB (Q= 32,T= 1) : 3.787 MB/s [ 924.6 IOPS]
Random Write 4KiB (Q= 32,T= 1) : 0.957 MB/s [ 233.6 IOPS]
Sequential Read (T= 1) : 41.735 MB/s
Sequential Write (T= 1) : 33.551 MB/s
Random Read 4KiB (Q= 1,T= 1) : 3.789 MB/s [ 925.0 IOPS]
Random Write 4KiB (Q= 1,T= 1) : 1.145 MB/s [ 279.5 IOPS]

Test : 1024 MiB [H: 0.0% (0.0/59.8 GiB)] (x1) [Interval=5 sec]

CrystalDiskMark 5.2.1 x64 (C) 2007-2017 hiyohiyo
Sequential Read (Q= 32,T= 1) : 40.865 MB/s
Sequential Write (Q= 32,T= 1) : 40.891 MB/s
Random Read 4KiB (Q= 32,T= 1) : 3.380 MB/s [ 825.2 IOPS]
Random Write 4KiB (Q= 32,T= 1) : 1.210 MB/s [ 295.4 IOPS]
Sequential Read (T= 1) : 41.733 MB/s
Sequential Write (T= 1) : 42.148 MB/s
Random Read 4KiB (Q= 1,T= 1) : 3.382 MB/s [ 825.7 IOPS]
Random Write 4KiB (Q= 1,T= 1) : 1.207 MB/s [ 294.7 IOPS]

Test : 100 MiB [H: 0.0% (0.0/59.8 GiB)] (x1) [Interval=5 sec]

Samsung Duo manifested exactly the same behavior. Now I am not sure what is going on.

I tested my old USB SanDisk Extreme PRO 128GB, which I use every day and I don't see significant speed difference (purchased about 2 years ago and saved speed tests), however I seen something similar on my old Corsair GTX 128GB, but not to the same degree (speeds were low untill I reformatted, then, speeds came back as they should be, actually testing it now, crazy fast on USB 3.0, still).

What could be wrong?

Any suggestions appreciated.

 

[waheedsawar]

This may or may not work. Try formatting the usb drives as ntfs

 

[Kisianik]

This may or may not work. Try formatting the usb drives as ntfs

Actually I did it already and formatted back to ExFat - I did already 3 formats for this drive, NTFS was just a bit slower than ExFat.