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Kioxia U366 128GB USB Drive review

Kioxia sent me the new Kioxia U366 USB drive to test. You may be thinking USB drives? Why would I still use those, we have online services and for local storage I could use a portable SSD which is way faster! You are certainly right, but there still is a place for the good old USB drive if you ask me.

USB drives are smaller than a portable SSD, work even when you don’t have internet access and they are cheap and reliable. That is why I still carry one attached to my car keys. I don’t use it a lot, but I does really come in handy from time to time!

Did I mention it is small? Very small…

Oh, and did I mention price? A 128GB USB drive like the Kioxia U366 I’m reviewing here will cost about 20 euro’s. Can’t complain I’d say!

The Kioxia U366

The Kioxia U366 is very small, even for an USB drive. (I’ve reviewed other USB drive from Kioxia that were compact, but not as compact as this one) The body is made completely out of aluminium and is just as wide as the USB-A connector and about 4 cm long. The back of the body features an integrated loop to attach it to a keyring or strap it to your bag. It is small enough to fit any small pocket. Because of the sturdy aluminium body it will have no problem being lugged around in your pants pocket or on your keychain at all.


The USB drive comes packed in a small but practical package. Instead of the usual packaging that you have to attack with scissors the Kioxia U366 comes in a clever package that can be opened without tools. Seems like a strange thing to write about in a review as you will only open it once, but some of these USB drive come packed in the most annoying and stupid packages ever. So kudos to Kioxia for doing it better!

Love the simple to open packaging!


As usual for any brand USB drive I didn’t have any problem with compatibility. The Kioxia U366 comes formatted in FAT so it works great on both a Mac and a Windows PC. The USB-A port on the Kioxia U366 is USB 3.2 Gen 1 Super Speed compatible and is backwards compatible to USB 2.0. That means you can connect it to almost any USB device and it will work without a hitch. If you connect it to any modern device it will use the fastest possible connection speed using the modern USB 3.2 Gen 1 protocol.


With the modern USB protocol the Kioxia U366 is capable of quite fast speeds. For the smaller models, up to 64 GB, Kioxia promises read speeds of up to 100 MB/s. And the 128 GB version can even go up to 200 MB/s. When testing I was truly surprised by this tiny USB drive. I’ve tested the stick on my M1 Mac mini both connected to the USB ports on my Mac and the USB-A ports on my USB-C dock. In both cases file transfer was very fast and stable.

I’ve added the screenshot of the Blackmagic Disk Speed Test below. I’ve ran the speed test for 10 minutes completing multiple read and write runs. The U366 does get quite warm whiles testing but this didn’t affect performance.

As you can see write performance was very good at a stable 40 MB/s (it started off at about 55 and dropped down to 40 after about 5 seconds, never dropping lower during the whole test). Read performance was even more impressive surpassing Kioxia’s own promise and delivering 224 MB/s. Not much more you can ask from a USB drive this small.


The Kioxia U366 USB drive is great if you are looking for a very small and dependable USB drive. Even in these times with online storage and blazing fast portable SSD’s a simple USB drive is great to keep in your pocket or bag.

With the U366 Kioxia delivers more than it promised, with really fast read speeds of over 224 MB/s. That combined with a small and durable aluminium body and attractive price makes the Kioxia U366 a no brainer!

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