Samsung Fit Plus USB 3.1 flash drive MUF-64AB

The Samsung Fit Plus USB 3.1 flash drive arrived with "Model" MUF-64AB and "Model code" MUF-64AB/APC. I think the code refers to the package for the Asia Pacific region. Your version might be different.

Who wants this device?

Lots of people want USB flash memory sticks. Most with experience of USB sticks will know the problems caused by the sticks protruding from a USB socket. One bump and your stick breaks or, worse, the socket in your computer breaks. The Samsung Fit Plus protrudes by only a small amount and should be safe when left in your computer on the desk top.

I would remove it for travel. There are smaller devices with less protrusion. I used some Sandisk devices small enough to leave in a notebook while travelling but one out of the two Sandisk devices failed when the plastic top fell off.

The device is available in a range of capacities up from the 64 GB tested here. Given the limited write speed, I would not use the Fit Plus at a higher capacity if I had to constantly fill them. At 256 GB, I would switch to an SSD in a USB enclosure.


My Fit Plus 64 arrived formatted as one big exFAT partition. I will change that to Ext 4. There was no junk software supplied.

The device is listed as waterproof, something I will not test. It is "temperature proof" but no there is no temperature range listed. Xray proof probably means the metal shaft of the USB plug runs up over the chip. Magnet proof applies to all flash memory.

Shock proof is another claim and is not relevant to flash memory. I would be more worried about someone bumping the memory stick while plugged it. The Fit Plus has the advantage of only a small protrusion when plugged in which makes it safer than most USB sticks of a similar speed or capacity.


A benchmark in a machine way faster than the Fit Plus 64 produced the following speeds. Compare them to the advertised "up to 300 MB/s".

 File size in MB 


 Write speed MBps 

 Read speed MBps 












Writing a 16 GB image to the Fit 64 ran at an almost constant 29.5 MBps in a machine that could easily do more than ten times that speed.

This test is on a Raspberry Pi 4 using the raspberry Pi Diagnostics.

Raspberry Pi Diagnostics - version 0.13
Test : SD Card Speed Test
Sequential write speed 27793 KB/sec (target 10000) – PASS
Random write speed 4483 IOPS (target 500) – PASS
Random read speed 3250 IOPS (target 1500) – PASS

When do I use it?

In a Raspberry Pi, it is a good alternative to a microSD card for the system boot disk and some storage. It is a match to a Pi 4 for many uses and a proper SSD is better when there are frequent writes. Based on the first details of the Pi 5, I would choose something faster for the Pi 5.

The Fit Plus 64 looks like a good choice for use in my television and car for storage of music plus video. I used a Sandisk Ultra Fit in my car and the plastic top part fell off in the heat. I may test the Samsung Fit Plus in the car this summer.

The safe space in the TV USB section would fit something longer than the Samsung Fit Plus but not as long as my 64 GB Sandisk Extreme Go. As a comparison, the Go is USB 3.1 but has a slower read speed. The Go does have a faster write speed some of the time, about three times as fast at the peak, but quickly drops off down to lower than the Samsung.


The short length makes the Fit Plus a good choice for something protruding from your computer for hours at a time when people may bump it. The classic accident. Someone slams a book/box/box of books down on your desk.

The length and square shape is just enough to possibly rip the inside of your beautiful new shoulder bag. Something like the Sandisk Ultra Fit would cause less damage.

The temperature proof claim makes the Samsung Fit Plus a candidate for use in cars and other hot environments. I would not use it in a dashboard USB socket as the Australian sun destroys anything not UV protected. I will use it in a shaded USB socket for my collection of music.

The USB stick is short enough to use in a Raspberry Pi open case but not an enclosed case. The pocket style cases for the Pi 4 are a better fit for a top of the line microSD card. Desktop usage should be fine. Given that the Pi 4 and Pi 5 have only two USB 3 ports, plugging this device in one port limits your expansion. There are microSD cards that can compete for similar write speeds and would be just as useful for many projects.


The best reason for using the Samsung Fit Plus is not breaking the USB port in your notebook. Similar situations, like the USB ports at the back of my TV, may give you more choice in size but often not enough for the big fast USB memory sticks.

The next option for my TV, when I need more capacity, is an SSD in a USB enclosure with a short cable. The SSD can then fir on the back of the TV without protruding off the size.

The Samsung Fit Plus write speed was a little bit low at the start but remained steady, making it faster than competitors with faster initial speed but a real slowdown after a few gigabytes.

The Samsung Fit Plus was also a good price for the mix of capacity and speed. When you buy a popular model in a major brand, there is more chance of finding the project on sale at an excellent price.


The Samsung Fit Plus competes against a small range of good short USB memory sticks. The regular price makes it close to the Sandisk Ultra Fit. Both brands are often on sale. For use indoors, I might buy either. After the Sandisk failed in the hot car, I chose the Samsung for my car. For use indoors, either should work. Buy whatever is cheapest if one of them is on sale at a huge discount.

When you need more capacity, choose an NVMe SSD in a USB enclosure. Your time is more valuable than what you will waste waiting for the device to write hundreds of gigabytes.