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How To Test Your USB Flash Drive Speed

Luis Silva

*As an Amazon Associate, I earn a small fee from qualifying purchases. It doesn't affect any item's price or eventual reviews.


One thing that I love the most is to drive while listening to my favorite tunes.

The other day I was planning a car trip that I knew it would take a little longer than usual. Unfortunately, when I remembered I had some new songs I'd want to take with me, it was already time to leave. Then I thought: If I knew what my fastest USB thumb drive was, I'd probably still had the time to copy all the files I wanted.

So, I've decided to put all my flash drives and MicroSD cards to a speed test.

There are a couple of ways you can test your flash drive read and write speed:

Manual benchmarking

One way you can do this is to just sit in front of your computer with a stopwatch and time how long it takes to copy some files from your internal drive to every one of your flash drives. While that can seem a little bit tedious, in my opinion, it still is the most reliable way of keeping a score. If you're like me and prefer real-world tests, you're in the right place. If you prefer to download an app to do that for you, you can just skip to the next section right away. Otherwise, stick around and check the suggestions I have for you.

Firstly, you'll have to decide what kind of test you want to do so you can choose the right files to test with. Me, I just want to do a test with some mp3 files, so around 300Mb of them should be enough. If you choose a bunch of small files (less than 1Mb each), 150Mb is a good starting point. If, on the other hand, you want to do a test with something bigger, like video files, 300 to 500Mb should be just fine.

Keep in mind that small files take longer to copy so the average speed will be lower than copying mp3 or mp4 files. Also, you'll have to figure out if your USB port is 2.0 or 3.0 (at least). If your port is blue, like in the picture below, then you have a fast USB port. If it's black, that doesn't mean they are slower (2.0) unless you have a pretty old pc, then they probably are.

The next thing you should know is that the flash drive itself "should" also be blue (3.0), like in the picture below. If you want to know more, see the Best Buying Tips section down at the end of this post.

That's it, I guess you're good to go. Now put some files in a folder on your internal storage drive, insert a flash drive, start copying them and start your stopwatch.

In my tests, 300Mb of mp3 files took around 42 seconds to copy to a Kingston DataTraveler G4. This means that my flash drive can write data at the speed of 7.14Mb/s (300Mb/42s).

On the other side, my Kingston MicroSD class 4 16Gb card took just 34 seconds to finish, so it's good to know that a reasonably low-end card was able to write at least at 8.82Mb/s. But if you go towards a more high-end MicroSD card, you can expect something around 23Mb/s. At least that's what I got with my Sandisk Ultra 128Gb MicroSD XC1 class 10.

Also, don't forget that if you use a card reader, it also should be USB 3.0 compatible.

Now that you got the hang of it, you can do all kinds of tests to your ports, flash drives, memory cards, and external drives.

But what about using an app to do the tests for you?

App benchmarking

If you know me a little bit, you know I'm all in for store apps or portable apps, so, in these tests, we'll prioritize those apps over the ones you have to install on your PC.

CrystalDiskMark (v6.0.1)

CrystalDiskMark is one of the tech-geeks go-to apps. It allows you to refine your tests like the file size, how many times the test runs or setting up to four queues and threads for sequential and random testing. If you’re wondering what all that means then you should probably go back to the Manual benchmarking section of this article or choose another app.

Also, be aware that 1 MB/s of speed isn't truly 1024Kb/s but only 1000Kb/s.

As you can see on this screenshot, my 16Gb class 4 card just got crushed in the random write tests. My flash drive didn't do much better either, but at least my real-world tests got me better sequential write results than this app.

You can download CrystalDiskMark here at the MS Store.

USB Flash Benchmark

USB Flash Benchmark can also be used to test the read and write speed of any USB Flash Drive. Unfortunately, I wasn't able to run a test on my MicroSD card on it. USB Benchmark Speed Testing is done via small 1KB file chunks up to large 16MB file chunks, and the results are graphed so you can see exactly how well a drive performs with varying file sizes. Optionally, results can be stored on the USBFlashSpeed website.

All you have to do is plug in the drive, select it, then click the relatively big Benchmark F: button (the drive letter may vary).

What I like about this tool is that it performs a variety of tests (15 in total) showing you how your drive performs in various situations. I wish it had some options because I'm only interested in the writing speed and the graph doesn't help that much.

You can download USB Flash Benchmark here (portable version)


UserBenchmark is a generic PC benchmark tool focused on comparing results with other users and components. They have tested over 16.000.000 PCs up to date. This app will test your CPU, GPU, SSD, HDD, RAM, USB, and FPS.

If you're really tired of slow flash drives and want to buy the best you can get, you can start by going to usb.userbenchmark.com/. You can search and sort to your liking. I personally like to sort by average benchmarking, where the speeds are combined to form a single effective speed which measures performance for tasks such as copying photos, music, and videos. But if you're looking for a flash drive for a specific use, you can always sort by Peak Write Speed (MB/s) if you mainly work with big files or Peak 4Kb Write Speed (MB/s) if, on the other hand, you usually deal with lots of small files (at about 4Kb in size).

If you don't have the time or if this seems too complicated to you, I have a couple of suggestions for you. Just head down to the Best Buying Tips and check them out.

Now back to my personal tests. Unfortunately, my Kingston flash drive scored very low compared to other flash drives, with a bench score of only 22%, despite performing above expectations. Read speed was pretty much in line with the other tools and Write speed was a little bit higher: 14MB/s. I highly doubt I will ever get that in any real-world use case scenario.

Unfortunately, I wasn't also able to run a test on my MicroSD card on it.

When UserBenchmark finishes its tests, it will generate a report that will open on your default browser and the flash drive test speed will look something like this:

You can download UserBenchmark at www.userbenchmark.com clicking on the Free Download button. It's portable, so you don't need to install anything on your PC.


USBDeview is a portable utility by Nirsoft with a nice feature that enables you to uninstall current and any previous USB devices attached to your PC. You can also publish your bench results to the Nirsoft Speed Tests webpage for viewing and comparison.

To start, find your USB device which should be highlighted in green with a device type of Mass Storage, right click on it and select Speed Test (Ctrl+T). Click Start Test, and it will sequentially read and write a 100MB file to get the scores. While you're at it, you should also check your device properties. It may have some info of interest to you.

This is what this tool looks like and the corresponding report of my flash drive speed. By the way, I think this tool is also being a little optimistic with the 12Mb/s write speed report.

You can download it here, from softpedia.com

Check Flash

If you want options, Check Flash is one of the most advanced tools on this list. His principal function is to scan a USB flash drive for possible errors, but it also runs a read and write speed test while doing so.

I personally don't recommend this as a go-to bench tool, unless you also want to test your entire drive for errors (a good idea if your flash drive is kinda old or had a very intensive use since you bought it).

The Use temporary file method is non-destructive and will fill all the remaining space on the drive with a temporary file and then perform an error check on it while recording the read and write speeds. If you have an (almost) empty or slow flash drive be aware that this test will take a while to finish.

This is what my MicroSD card looks like:

1.89Gb of free space took almost 10 minutes to finish.

And this is my flash drive test:

4.5Gb of free space took almost 15 minutes to finish.

You can download it here, from softpedia.com

Best buying tips

Many people buy solely on the storage size of the device for the price and do not take into account how fast or slow the drive is. When you're buying a new flash drive, USB 3.0 is mandatory. In fact, some may say you should aim for USB 3.1, even if your (old) PC (or mobile) will cap it at 3.0 speeds.

Even if you buy a USB 3.0 flash drive - you probably have noticed this already - the read and write speeds may vary a lot, even within the same brand. So, you'll have to pay attention to the announced read and write speeds but just keep in mind that those values are generally overstated. They may only get those speeds if they are used in a specific use case scenario.

If this seems too much for you and you'd still like to have an outstanding flash drive, you're in the right place. I've compiled a short list of flash drives you should really consider.

One of the best all-around flash drives (128Gb):

Check prices here, on Amazon.

With a peak writing speed of 263Mb/s* for big files and 12.3Mb/s* for small files.

And a cheaper but also good flash drive (64Gb):

Check prices here, on Amazon.

With a peak writing speed of 98.2Mb/s* for big files and 3.2Mb/s* for small files.

If you're looking for something affordable and swifter while copying small files (16Gb):

Check prices here, on Amazon.

With a peak writing speed of 62Mb/s* for the big ones and 10.1Mb/s* for the small ones.

*Accordingly to userbenchmark.com.

If you're looking for deals on fast flash drives, check these out:


Getting the best bang for the buck when buying a flash drive isn't easy. So, we kinda end up having lots of flash drives with mixed speed results. I hope by now you've identified your best flash drives and in the end, if you're a bit disappointed like I am, you can always buy a couple of new snappy flash drives and never miss out on copying your favorite tunes to listen wherever you want.

Were you able to test your flash drives? Do you already have a super-fast flash drive? Do you prefer manual or automated speed tests? Do you still have any doubts? Head on to the comments section below and share your thoughts.

Please, don't leave with any unanswered questions because I may have an answer, and we'll probably be helping someone else too. Just leave them in a comment below or send me an email and I'll be glad to help.

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