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me55

macrumors regular
Original poster
Jul 26, 2019
132
63
I have an interesting issue with a USB 3.0 UASP-capable hard drive (1TB 7200rpm). Formatted the drive in HFS+ unencrypted it is very fast, read and write over 100MB/s and high IOPS. The same drive formatted in HFS+ encrypted shows a little bit lower reading performance, but the writing performance suffers a lot (60MB/s at best). Different firmware versions on the controller chip of the enclosure (JMS578) make no difference in speed, only spindown on eject is supported with some (which is nice).

A USB SSD in a different enclosure formatted the same way does not suffer from this, in both cases it does over 200 MB/s. So the speed issue is not because of the computer.

Anyone got an idea what could cause that?

2018 MacBook Pro 15" running Catalina, but the issue was present in Mojave.
 
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