SD cards exist in three different form factors these days. There is the standard SD card designed in 1999, then we got the Mini-SD card which made its debut in 2003 and the Micro-SD card which appeared in 2004. These three form factors have been with us all this time and even though their design remained the same, a lot has changed in terms of performance and reliability. Most modern laptops, smartphones, gaming consoles and other devices feature an SD card slot of one shape or the other. There are also countless adapters and SD card reader devices which you can use as an add-on for your current hardware.
SD card slots have always been a useful feature as they allow for easy and significant memory expansion for the device in question. Regardless of how popular cloud storage services are currently, it is always a good idea to have some form of physical storage in place. You might want to back up some of your photos or simply need more local storage to play games on your phone. It is more convenient, for an example, to store large video files for future editing on SD cards or you might be going to a remote location and you want to have some Netflix shows to watch offline.
Regardless of your specific reasoning, SD cards are here to stay and there is a perfect SD card for your use case. For this reason, we have decided to create this guide which you can always fall back to, in order to refresh your knowledge and understanding of different SD card types, what really matters for your application and how to get the most out of your hardware.
Overview of SD Card Types
SD Cards were introduced to the market back in 1999 and have remained the most popular choice for portable storage to this day in devices such as digital cameras to the highest extent. In one form or the other, SD cards are also used in devices such as car GPS computers, handheld gaming consoles, tablet computers and many more. The SD is an abbreviation for “Secure Digital”.
The Original SD Card
As mentioned in the introductory paragraph, the original form of SD card made its appearance in 1999 and from that point onward the design remained the same, but the performance and reliability features have strongly improved.
The first notable step up in this space occurred in 2006, when the SD standard met with the ongoing demand for more capacity. Therefore, the “Secure Digital High Capacity” card was introduced to the market, extending the maximum capacity up to 32 GB. Prior to this, the storage capacity was capped at 2 GB. If you have an old digital camera, its maximum storage capacity might be limited to a 2 GB SD card, so keep this in mind. With the introduction of 32 GB SD card, the new era of digital photography was ready to set off as this was a significant improvement, allowing for higher quality content that took much more storage space.
The SDXC (“Secure Digital eXtended Capacity”) card is classified as an SD card with significantly larger storage capacity, but also feature much faster read and write speeds. The SDXC standard was introduced to the market in 2009 to further improve upon SDHC technology. Capacity varies from 64 GB to a maximum of 2 TB. SDXC cards are identical in exterior design and format to the SDHC cards, and while they fit the regular SD card slot, not all devices are able to read or write data from and to these cards. It is therefore important for you to check if your device does have an SDXC compatible slot.
Continuing with the rising demands in storage space and speed, SDUC (“Secure Digital Ultra Capacity”) was introduced as a concept in 2018 and it represents the next step in improving SD cards as we know them. It is expected for these cards to be able to hold up to 128 TB of data.
What SD Card Speed Is Right for You?
Different vendors label speed in specific ways which are not always interconnected. The micro SD card class is often overlooked as a parameter when purchasing a new card. Today we know of the following speed classes:
- Default Speed – 12.5 MB/s
- High Speed – 25 MB/s
- UHS-I – range from 12.5 MB/s to 104 MB/s
- UHS-II – range from 156 MB/s to 312 MB/s
Also, the SD Association defines classes for video recording capabilities, determining the requirements for successful recording depending on resolution and framerate. There are Class 2, Class 4, Class 6, and Class 10 SD cards. These classes feature writing speeds of up to 2 MB/s, 4 MB/s, 6 MB/s and 10 MB/s, respectively. Class 10, on the other hand, can go up to 90 MB/s.
The guys over at GamerHeadlines.com made a research in their latest article on the best SD card for Switch where they mentioned that for gaming, the best SD card speeds should be somewhere around 120 MB/s in read speeds and 60 MB/s in write speeds. But let’s dig a bit deeper in to the topic.
How Important SD Card Speed Really Is?
Speeds which have been declared by the vendor are one thing, real world performance is the other one. For this reason, when you are purchasing a new SD card for a device which recommends a Class 4 card, it is a good idea to step up and get a Class 6 card. This will prevent any corrupted footage from occurring due to data fragmentation or other related issues, basically ruining what you have been working on.
Another important issue to mention is the response time of slower cards when using DSLR cameras in their RAW mode. The slower your card is, the more time it will take for your camera to be ready to take the next shot. For burst shooting this is of upmost importance and it is a general rule of thumb to get a Class 10 SD card for more advanced use cases such as this. In some cameras you will even get a message indicating that the recording setting is basically too intense for the SD card currently inside the camera and that you need to upgrade its class to work as intended.
The minimum write speed represents speed below which the writing of files onto the SD card will never drop below. It is important to note that this is the minimum and sustainable rate at which this happens, and it is quite important for high resolution video recording, since the file may appear stutter during playback.
Maximum read speed basically indicated the rate at which files are read from the SD card. A consensus is that the reading rate is not as important as writing rate and it is usually more of a marketing thing than real world performance figure.
How to Determine the Best SD Card Price?
Once you have gone through other critical requirements such as the speed and format which suits your use case, it is also a good idea to determine which brand will provide you with the largest storage capacity as prices jump around quite a bit. Basically, you want to get the best bang for your buck when it comes to storage capacity, as more is always better in this case. You will find that prices do not drop or rise linearly as you might expect, so a decent 256GB SD card price at a discount might be a much better deal than a 128GB, even though it is more expensive at first.
Probably the most popular approach towards this is to calculate prices per GB of storage capacity, so you get a simple overview about which brands or deals might provide you with the best values at the time of purchasing. See table below as a guideline:
|Price per GB ($)
Is Data Transfer Speed Slower with an SD Card Reader For PC?
Contrary to the general opinion on this matter, there should be no effect of the SD card reader for PC in terms of read or write speed. These adapters are designed in a way to extend the micro-SD card connectors passively, so there is no reason for them to deteriorate the transfer speed. Being an added electrical connection, though, reliability might be an issue in case of bending or misuse of the adapter itself.
How to Format SD Card?
Once you purchase a brand-new SD card you can use it straight out of the box. Most devices such as smartphones or cameras require for the card to be pre-formatted even when new so keep this in mind if you are in a hurry. The formatting process prepares the SD card for normal usage, making sure that all the data which is eventually put onto it is accessible and does not go corrupt.
The easiest way to properly format your SD card is to simply install it in your device and follow the steps (if necessary) to allow your device to format the card as required. If, in any case, you are unable to format SD card this way, you can always try formatting it on a Windows or Mac computer. Depending on your hardware and type of SD card you have, you might be able to do this without any extra hardware. If there are no slots to insert your SD card on your computer, you can use a SD card adapter and format the card that way. Both Windows and Mac have built-in formatting tools which makes it easy to force-format the card to either FAT32 or NTFS, while also being able to set a name for the card as well as some other simple options.
How to Format Micro-SD Card?
Other than the shape and size of the MicroSD Card, everything else is the same basically. The same methods for formatting a SD card apply to MicroSD cards. If your hardware does not have a microSD card slot, you will need to get an adapter though.
How to Remove Write Protection on Micro-SD Card?
One of the most common minor issues a lot of users run into is when the SD card indicates that it is write protected. In this state you will not even be able to format the card, so in case you run into this issue, here are some of the most convenient and fool-proof solutions.
Physical Write Protection Lock Switch
All SD cards have a tiny switch on the left-hand side which serves as a write protection activator so to say. However, micro-SD cards do not have any physical buttons or switches which serve the same purpose so if your micro-SD card is write protected, you may need to use a microSD card adapter to physically override the write protection on your microSD card. Simply insert your microSD card into the SD card adapter, make sure that the switch is not set to the “lock” position and give it a try.
Using Command Prompt to Set MicroSD Card Properties (Windows)
If the above method did not work and your SD card is write protected still, you can try observing properties of the mounted card and change them accordingly. Here are the steps you need to take:
- Press Start and type in “cmd” (make sure you access it as an administrator)
- Within the command prompt window type in “diskpart”.
- Next, type “list disk”. After this you should be able to see a list of all storage devices connected to your computer.
- Under the “Disk ###” column locate the correct device (SD card) and note the number in the list. You can use the “Size” column to determine the correct label.
- Type “select disk x”, where “x” marks the correct label for your SD card. Now you have selected the disk to work on in the next step.
- Once the correct disk has been selected, type in “attributes disk”. If you see “Current Read-Only State: Yes”, you have a write protected SD card.
- Finally, to clear the write protection attribute from your SD card, type in the following command: “attributes disk clear readonly”. You should see the “Disk attributes cleared successfully.” message and the microSD write protection has been disabled.
Low Level Format
If above steps did not work for you and you are still having the sd card write protected error, your best bet is to use a low-level formatting tool, such as the HDD LLF Low Level Format Tool. This software provides you with an option to perform a very low-level format on your microSD card, which consequently overrides some of the software limitations and rules set by the manufacturer of the card. The software is free for home and personal use, just keep in mind that this is a very thorough method of formatting, so you will not be able to recover any data from your card in case you need to do that in the future.
Which Is the Best SD Card Repair Tool?
It is not that uncommon for people to unintentionally damage their microSD cards. We all use these little cards for specific purposes and in cases of microSD card damage it is important for you to know that there are solutions you can take to reverse some or even all data corruption that took place with the mishap. Obviously, if you are reading this after damaging you card, the last thing you want to learn is about backing up your data but feel your way through the pain and learn from your accident, as this is the best and most efficient way for you to simply ignore the SD card not showing up issues and simply restoring your files from a safe backup.
Now that we got that critical point out of our way, let us look at some real solutions for the problem you are having. In cases where the damage to the card is minimal and you can see your SD card once you insert it into your computer, you can try the built-in repair tool that comes with your Windows installation. Simply right click on your SD card, select “Properties”, then select “Tools” tab and click on the “Check Now” button to initiate the check and fix process.
If your microSD card not detected, there is an additional step you can take to forcefully wake it up from its slumber. In Windows 10, right click on your “My Computer” icon and select “Manage…”. This opens a slightly advanced configuration tool which shows all drives connected to your computer at a lower level. In case your microSD card is still alive and kicking, you will be able to see it here, even though it may not be visible in the regular “My Computer” window.
In cases of even more severely damaged SD card, there are commercial tools such as the “DiskDigger” tool, which has a free trial period, and you can purchase a license for just $14.99 which is a decent price for what you are getting. Basically, by using this tool you can extract some or all the files, resolving your SD card problem to a certain extent. However, software tools are limited in their efficiency so you should never rely on these programs to resolve your issue once something happens. Once again, if you keep any important files on your SD cards, make sure to back these up onto another physical media or a cloud storage service preferably to avoid all the problems that will catch up with you.
Take Care of Your SD Cards!
As convenient and powerful SD cards are, they are also quite fragile and sensitive towards physical damage and general weathering. The least you should make use of is the SD card holder which can be purchased anywhere online and come in a variety of shapes, sizes, and colors. When not mounted in a device, you should put your SD cards in a holder and store them in a dry environment to preserve data on them, if any, as well as their overall functionality.