Makes sense. I recall the 2018 iPad Pros having NVMe level write speeds while the Samsung T5 maxes out at around 500 MB/s write then you've also got the exFAT overhead. Certainly would be interesting to see if the Samsung T7 will be faster.
I just ran Jazz Disk Bench app on my 2017 iPad Pro 12.9 512GB (88% full) and got the following with TestSize(Seq): 1G and TestCount(Random): 16384.
View attachment 1686579
I ran CrystalDiskMark on the T5 from my laptop -
CrystalDiskMark 6.0.2 x64 (C) 2007-2018 hiyohiyo
Crystal Dew World :
https://crystalmark.info/
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* MB/s = 1,000,000 bytes/s [SATA/600 = 600,000,000 bytes/s]
* KB = 1000 bytes, KiB = 1024 bytes
Sequential Read (Q= 32,T= 1) : 435.059 MB/s
Sequential Write (Q= 32,T= 1) : 255.001 MB/s
Random Read 4KiB (Q= 8,T= 8) : 149.140 MB/s [ 36411.1 IOPS]
Random Write 4KiB (Q= 8,T= 8) : 74.653 MB/s [ 18225.8 IOPS]
Random Read 4KiB (Q= 32,T= 1) : 93.441 MB/s [ 22812.7 IOPS]
Random Write 4KiB (Q= 32,T= 1) : 48.547 MB/s [ 11852.3 IOPS]
Random Read 4KiB (Q= 1,T= 1) : 13.327 MB/s [ 3253.7 IOPS]
Random Write 4KiB (Q= 1,T= 1) : 19.985 MB/s [ 4879.2 IOPS]
Test : 1024 MiB [F: 0.0% (0.0/465.7 GiB)] (x5) [Interval=5 sec]