Design and manufacturing quality: aluminum and plastic, I saw (often) worse and (rarely) better.
Performances: they are impressive. the announced theoretical speeds (260MB / s read, 240MB / s write) are required in test mode (CrystalDiskMark, modern PC equipped with an internal SSD, ASUS USB 3.0 Boost activated, large files). This is faster than a conventional hard disk SATA 6!
In the "real world", it is getting a little course, but not that much: copying a large file to the internal SSD is the key to 140 MB / s, and the copy from the key to the SSD to 205 MB / s.
This key really takes advantage of the USB 3.0 performance, which is not always the case with other key so-called USB 3.0, I have one that makes 82Mo / sec reading and 11MB / s to writing.
In short, a real key that USB 3.0 external SSD can replace a small capacity with a better ease of use (no wire to connect).
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