How To Test SD Card Speed And Capacity [Free Tool 2022]

SD Card: How To Test Their Speed And Capacity

We all have come across a time where we run out of storage and how we wish we had a trustworthy storage device that helps keep all of our memories and important files safe. That is where the SD card comes in. It is most common in mobile phones these days and is used to further expand your phone storage. However, there is one thing that people should keep in mind while purchasing an SD, their speed. 

We can test the speed on the PC with different tools to know which is the fastest SD card. As some people sell fake products in the market, we should be aware of those by checking the product to be legit.

About SD Card

SD card or Secure Digital card is the latest generation of memory cards that we can use in devices nowadays such as mobile phones or DSLR to expand the storage. It is a portable device as the pen drive that is based on semiconductor flash memory. SD card is a non-volatile memory card that is developed by the SD card association.

Memory cards these days have shrunken in size so well that it can fit on tip of your finger. Back in the old days to people used to carry big boxes in the name of storage but nowadays it has been a lot easier with the introduction of SD cards by companies such as Panasonic, Toshiba, and SanDisk. Capacities have reached up to 1TB for a tiny SD card and they support various write and read speeds. Tasks such as video recording and transferring media have never been much easier but how to test the actual write and read speed done by an SD card? Let’s find out

How To Test SD Card Speed?

Lately, there has been a lot of cases where the SD card sold by a store is fake. There has been this one area in flash memory storage that people are more prone to making fake memory storage. Devices such as the SD card, USB flash drive, and SSD drives have been affected by this unethical act. It is easy to hide the fake product from the actual one and people are being scammed one way or the other.

This problem is a lot more common than you think it is, even in places like eBay and more popular Amazon and other legit retailers have been caught doing such activity. This brings us to one reason to check the device before purchasing them. Seeking for the ones with warranty and having a legit tag to make sure there is no size difference and the product is legit. 

Having the read and write speed claimed by the company is what you should be looking for because those are the areas where people get scammed. They charge you less price for a good product which may lead you to think that it’s too good to be true.
Here are some methods or tests that you can run to check whether the product you buy is the actual thing or not.


H2testw is known to be the most popular tool for checking the memory to see if they are the correct capacity you bought. Back in 2008, the scam for providing lower space than mentioned was started where people used to make money out of selling storage space less than mentioned in the box or the packaging. 

With H2testw you can easily check the storage space of a memory drive by running the drive hours or even days on larger capacity drives if they have a slow write speed. However, this would be a price worth the pay because you are preventing yourself from getting scammed with just a simple test.

How this works is by writing large files such as a file covering up 1GB to a free space and then reading them back. If the read data is not the same as the data that was written, there is a chance that the device has an issue. Another example would be if you think the drive is only 8GB but they advertised as 32GB you can simply do a 10GB test of the data instead of the whole 32GB, this way you can have a custom amount of data test.

How H2testw works can be further simplified in the following ways

  • Go to the internet and search H2testw, download and install the software and run it on your PC.
  • Open the app and specify the folder where you want to write your files by selecting the “target” button
  • Set the data of your choice.
  • Finally, press the “write+verify” button to check your SD card speed.

Fake Flash Test

The fake flash test is another application you can use to check the read and write speed of your data or memory drive. This tool is pretty similar to H2testw as this application also checks the capacity of the drive-by estimating the read and write speed. The fake flash test has a unique and handy feature called the “quick size test” where you can easily determine the size of your drive by writing and reading 512byte of data at a random sector across the drive. This lets you with faster results if you have a larger capacity card.

Note to the user is that a “quick size test” is not a good way as it wipes up any data on your card. There is no option to test the card without data loss so if you need those data you can first back up then only run the test. This application is focused to fix the issue with H2testw which is the long time that h2testw takes to complete the process. Besides that, everything about this application is developed to do the same thing. For instance, the written files are done with the intervals of 3GB, 5GB, 9Gb, and so on so, you should be clear that when your fake drive has 4GB instead of 16GB you should now clearly know after the 5GB read test.

Here’s a step by step process on how to run the application

  • Go to the internet and search for FakeFlashTest, download the application, and install it on your PC.
  • Open the application and run the “quick size test” first to confirm the actual size (This is a high-risk step as it erases all your data)
  • Next, write the data on free space and let the drive read it back to verify.
  • Check the results.

Chip Genius

Chip genius is a program that doesn’t touch the data on the drive at all. Instead, it takes the information from the memory chip inside the drive to know the actual capacity of the drive. Previously we saw that other programs write the data onto the disk and reads it back to see if the whole data gets read but it’s not the case with Chip Genius. 

Follow the steps to know how to check the speed or capacity of the drive

  • Search for Chip Genius, download and then install the program on your PC
  • Open the program and run the program
  • After the program is being run, it will give you the flash code and model number of the chip
  • Copy the line that says Flash ID code and paste it into any search engine
  • Know your drive speed and capacity.

Black Magic Disk Speed Test

This next speed test for Mac owners to verify your SD card, the Blackmagic Disk Speed Test was designed to test the speed of larger drives but it also works on SD cards. With the read and write speed, this app lets you write larger data to your storage device and then reads it back to verify the performance it gives. 

However, this process of writing and then reading it back takes a lot of time but know that it is legit and this is an excellent tool to verify the speed of your SD card. This app is simple in terms of usage but as mentioned takes a lot of time.

Flash Drive/ Card Tester

This tool is used for testing flash drives, SD cards but mainly for detecting drives with fake capacity. The usage of the system is similar to that of H2testw by writing data to the device, reading it back, and then comparing the two like the above-mentioned program. If there is an error while running the program, it indicates that the drive has a lower capacity inside it. 

To run the test you need to select the memory card then choose the test type stating “write, read, and compare” and start the test. This application also lets you compare the results for later use and just carry on with the writing and reading part. You can run a separate test to compare the results.

SD Card Speed Test On Android

To test your card speed on your android phone you need to download an SD cards speed test tool which you can find free on the internet. After you run the program you will know the speed of your card. Some of them are A1 SD Bench or SD Card Test. Run the program and see the results for yourself.

Types Of SD Card

SD (Security Digital)

SD cards are old memory cards that have a storage capacity of up to 2GB, these cards are formatted by default in FAT16. The dimension of this card is 32 x 24 x 2.1 mm. This card was developed to improve the multimedia card standards from shape, thickness, capacity to even transfer speeds. 

Micro SD

Micro SD cards are simply miniature versions of the SD cards. These cards are also old and can have a maximum storage capacity of 2GB. Its dimension is 15 x 11 x 1 mm. The size of this card was seen in the newer version but people took it as micro SD cards which is technically wrong.

Mini SD

These cards are smaller than the regular SD cards but bigger than the micro SD cards with a dimension of 21.5 x 20 x 1.4 mm. The storage capacity of mini SD cards is the same as the SD or the micro SD.

SDHC (Secure Digital High Capacity)

SDHC cards are as stated by the name have a storage capacity bigger than that of SD cards. These cards can have a storage range from 2GB to 32GB. Only the size and the dimension of these cards are the same as SD cards. These cards are also formatted by default in FAT32 unlike FAT16 in SD cards. 

Micro SDHC

Micro SDHC is a smaller version of the standard SDHC in terms of size but the storage capacity and everything is the same as SDHC that is 32GB.


This type of cards have the same size as the mini SD cards but with a storage size of up to 32GB

SDXC (Secure Digital Extended Capacity)

SDXC is the most improved variant of the SDHC. This card can hold up to 2TB of storage space with the same physical properties and also include a faster transfer speed. The default format used by SDXC is the exFAT file system.

Micro SDXC

Micro SDXC cards are similar in terms of the storage capacity of 2TB but have a smaller physical aspect. They are much faster than SDXC.

SDUC (Secure Digital Ultra Capacity)

The most evolved card to date is the SDUC. Their storage capacity can reach up to 128TB theoretically with the same physical build of SD/SDHC/SDXC cards. SDUC also uses the exFAT format.

Micro SDXC

Micro SDXC is the smaller version of the SDUC with the same size as the microSD/micro SDHC/micro SDXC cards. However, have a faster write and read speed and has storage space of SDUC.

SD Card Speed Rating

SD card speed rating is important as different cards may have different speeds. This speed rating enables you to distinguish and classify the card’s speed properly.

Firstly, the SD Association has twoUHS speed category, UHS speed grade 1, and UHS speed grade 3. The speed grade is used to determine the minimum write speed. In the case of UHS speed grade 1, it supports a minimum write speed of 10MB/s while the UHS speed grade 3 supports a minimum write speed of 30MB/s. 

You can identify this by looking at the card represented by 1 or 3 inside the U symbol.

The higher the UHS speed the better. For the cameras, with 4k recording capabilities, you will most likely need a UHS speed class 3 SD Card. Also, with cameras such as the GoPro, you often require the UHS speed class 3. This will shorten the time required to download or transfer media from the SD card. 

All the manufacturers usually measure the speed in terms of megabytes per second or MB/s. This is not the same as Mb/s. For instance, a byte has 8 bits so megabytes multiplied by 8 is 80MB/s which is roughly 640Mb/s.

One thing to keep in mind while purchasing an SD card is the speed rating, make sure the card is UHS speed class of 3. Also, the card must be formatted as FAT32 or exFAT, and also check the card write and read speed.

Identifying Fake Memory/SD Card

There are a lot of retailers trying to fool you by selling you knock off products. In this section, we are going to tell you about how you can identify fake SD cards.

Avoid Buying Cheap Memory Cards Online

We all look for cheap things on the internet and grab it once it hit your eyes. That’s what many people think as they want high-end products at a cheaper price. If you ever come across this situation, try to avoid it as much as possible because you can be sure that they’re trying to sell you fake memory cards

Fake Brand

Be aware of the brands that sell you these fake memory cards. Only buy from known companies that make quality SD cards such as Toshiba and SanDisk. These companies are trustworthy and only sell genuine products. If you ever think of buying cards from another brand, research first then only be sure.

Unrealistic Capacity

You can go on websites such as eBay and can find a micro SD card with a storage capacity as large as 2TB which is unrealistic. In reality, MicroSD can hold only up to 512GB of space.

Reduced Capacity

Now you know that people sell fake memory cards you must be aware of. The storage capacity written on the package and the actual capacity might be different. They might sell you once with a lower capacity model and charge you a higher price.

Issues In Fake Memory Cards

If you purchase a fake memory card you will immediately face issues like slow transfer speeds to data loss. Yes, there is a chance that you might face data loss by using fake memory cards. They might not work as smoothly as the original ones so if you get those fake memory cards return them as soon as possible.

Inspect Packaging

Before the purchase, you might want to look into the package. There might be a chance that you might find an issue with the packaging. You can identify right away that it’s a fake one. So keep an eye on the packaging the storage capacity and the brand that is being sold to you.


How To Know If Your SD Card Is Legit?

Using programs such as H2testw tells you how fast you can write and read the data on your card. It also checks the actual storage capacity of the memory card and not the advertised one. This will tell you exactly if you have a fake one or the real deal.

How Can You Tell If A Card Is Genuine?

Simply check the packaging and if the text on the SD card. If the text is poorly printed, it is most likely a fake one. Also, you can check the price on their website. If it’s cheaper and too good to be true it’s a fake one. 

What Does A Class Mean On An SD Card?

Each of the SD cards comes with a speed rating known as Class. The larger the number of classes the faster the write speed with minimum performance. It allows data to be written onto the card at a higher speed.

Related Article/Also Read:

Fake SD Card: How To Spot and Avoid Being Scammed


Every test mentioned above helps you to know the speed of your SD card. It also lets you know the capacity it can hold. This is an easier way to get rid of fraud or identify the fake ones. Running these tests can help you know the true capacity and true efficiency of the card. As mentioned, these tests do take time, and some put your data at risk. Therefore, choose wisely before you decide to run any test.

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