SanDisk Ultra microSDXC, 400 GB

Last updated date: November 15, 2019

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SanDisk Ultra microSDXC, 400 GB

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We looked at the top MicroSD Cards and dug through the reviews from some of the most popular review sites. Through this analysis, we've determined the best MicroSD Card you should buy.

Update as November 15, 2019:
Checkout The Best MicroSD Card for a detailed review of all the top microsd cards.

Overall Take

The SanDisk Ultra microSDXC, 400 GB memory card boasts a huge amount of storage for such a compact form-factor. The read and write speeds are rated as "Class 10" which means you'll not be waiting long to save or load content with this card.

In our analysis of 35 expert reviews, the SanDisk Ultra microSDXC, 400 GB placed 2nd when we looked at the top 9 products in the category. For the full ranking, see below.

From The Manufacturer

The SanDisk Ultra microSD UHS-I card gives you the freedom to shoot, save and share more than ever before. It is perfect for recording and watching Full HD video,(2) with room for even more hours of video. Transfer speeds of up to 100MB/s** help you move all your content blazingly fast—up to 1000 photos in just one minute.(6) Ideal for Android-based smartphones and tablets, this card’s A1 rating means that you can load apps faster too.(1) And, with capacities up to 512GB* capacity, this card lets you capture and store more than ever before. | * 1GB=1,000,000,000 bytes. Actual user storage less. | ** [for 64GB-512GB] Up to 100MB/s read speed; write speed lower. Based on internal testing; performance may be lower depending on host device, interface, usage conditions and other factors. 1MB=1,000,000 bytes. [for 16GB-32GB] Up to 98MB/s read speed; write speed lower. Based on internal testing; performance may be lower depending on host device, interface, usage conditions and other factors. 1MB=1,000,000 bytes. | (1) A1 performance is 1500 read IOPS, 500 write IOPS. Based on internal testing. Results may vary based on host device, app type and other factors. | (2) Full HD (1920x1080) video support may vary based upon host device, file attributes, and other factors. See official SanDisk website. | (3) Card only. See official SanDisk website. | (5) Download and installation required. See official SanDisk website. | (6) Based on 4.1GB transfer of photos (avg. file 3.5MB) with USB 3.0 reader. Results may vary based on host device, file attributes and other factors.

Expert Reviews

User Summarized Score

22,063 user reviews

What experts liked

The card can store up to 40 hours of full HD video.
- Legit Reviews
September 1, 2017 | Full review
This Class 10 card provides a huge amount of extra storage for your Switch, but is also compatible with Android smartphones and tablets as well as many other devices thanks to the included adapter.
- Lifewire
March 27, 2019 | Full review
This card performs flawless... not only in my Galaxy Note 4 phone but also in my camera. Leave it formatted in the default exFat and your good!
- Fone Arena
June 5, 2018 | Full review
We like that this MicroSD Memory card is speed rated “UHS-1” / “Class 10”, which means you get Full HD (1920×1080) video recording and playback. We also like that SanDisk has a “Memory Zone App” for easy file management it helps to organize data on Android-based devices and effortlessly back it up to the card. They also have “RescuePRO” back-up / recovery software which simplifies recovery of files that were accidentally deleted.
- Sourcetech 411

What experts didn't like

The SanDisk Ultra microSDXC UHS-I memory card costs $249.99 which is not cheap.
- Legit Reviews
September 1, 2017 | Full review
You may also need to update your system to work with this XC, or Extended Capacity, SD card.
- Lifewire
March 27, 2019 | Full review
The Sandisk Ultra 400GB memory card is certainly not a cheap product.
- Fone Arena
June 5, 2018 | Full review
- Sourcetech 411

Our Expert Consultant

Molly Thornberg   
Technology and parenting blogger

Molly Thornberg is a professional writer, creative and mom to four kids, living her best life outside of Dallas, Texas. With a love for all things tech, she is passionate about helping parents raise kids in the digital age. She writes about technology, parenting and humor on her blog Digital Mom Blog.

An Overview On MicroSD Cards

MicroSD cards are some of the most convenient storage devices for our electronics today. At only about the size of a nickel, a MicroSD card can store photographs, videos, documents and many other types of media in a conveniently small package. MicroSD cards can be found as the primary storage device for many cameras that are used today, as well as a significant amount of smartphones and even some other technology like the Nintendo Switch. Using these forms of external storage can help enhance how we use a lot of our technology as they provide a fast and secure way to save media that we find important, whether it be memorable videos and photographs or documents and records that need to be stored over time.

MicroSD cards are all the same exact physical size, which helps them pair up with so many different technological devices, but they can vary drastically in storage size. The storage capacity of a MicroSD card is measured in gigabytes (GB). Thanks to the recent advancement in this type of technology, the capacity of the most common brands of MicroSD cards is higher than ever, while the price is more reasonable than it has been.

“Before buying a microSD card, consider how much storage and what class of card you need to purchase,” advises technology and parenting blogger Molly Thornberg, who writes the Digital Mom Blog. “While about the size of a fingernail, microSD cards can store anywhere from 64 MB to over 2 TB of data. MicroSD cards are also categorized into classes, based on their minimum transfer speed. How you use the card determine which microSD class you need.”

To get a feel for what different storage sizes mean, a 128 GB MicroSD card like the Samsung MicroSD Memory Card, 128 GB, is capable of storing approximately 11 hours of 1080p HD video, which a lot of modern smartphones are capable of recording in. The 128 GB MicroSD card can alternatively hold somewhere between 20,000 to 80,000 compressed JPEG image files, which is a standard type of photo storage.

MicroSD cards were released in their tiny form factor after SD cards had already been around for a while. The SD cards were much larger, sizing up to nearly three times as big as the newer MicroSD cards. This is important to note as many older devices like laptops and cameras had built-in SD ports for those cards when they were more widely used. If you have a device that can take an SD card though, your MicroSD card will still fit easily inside through the use of an adapter. The adapters only require inserting the MicroSD card into a plastic housing that is the same size as an SD card, so the use of the adapter is not complicated.

Some companies will actually make your life easier when you purchase their MicroSD cards by throwing in the useful SD adapter with it. You can see this combination in a product like Inland Micro Center Flash Memory Card, 64 GB, which not only offers the adapter but wraps it into a 2-pack so you get two 64 GB MicroSD cards and two adapters. This type of deal will offer a great value to many users who might make use of the included adapter and additional memory card.

Speed is the key factor that sets varying MicroSD cards apart. Each popular brand will have its own unique terminology or color-coding for their memory cards based on the speed of the card and it’s not always super clear how much speed you actually need or want. Speed, in this case, refers to the speed at which the MicroSD card will transfer data in or out, which is often referred to as their read and write speeds. When a MicroSD card will be in your phone or another device that you want to work quickly so you aren’t waiting around as the files upload or download slowly, then you might seek out a card on the faster end like the Samsung MicroSD Memory Card, 128 GB. This Samsung MicroSD card offers a generous size to be able to store a ton of content, but it also boasts up to 100 MB/s read and 90 MB/s write speeds. These speeds will be perfect for filming 4k  UHD video footage, which is something you won’t be able to do so well with a slower memory device. Other benefits of these Samsung MicroSD cards are the variety of sizes they offer, which extend all the way up to a whopping 512 GB.

MicroSD cards require formatting to work in the device that they are plugged into. This formatting is sometimes set up to work behind the scenes, thanks to smart programming by the manufacturer. The SanDisk Ultra microSDXC, 400 GB is another huge storage device, still in its micro-sized package, but SanDisk went one step further to offer an app that will let you work seamlessly with the card when you want to transfer files to or from it. Their “Memory Zone App” will even allow you to set up your smartphone to keep a backup of all the programming it has on the SanDisk MicroSD card. This means you have the confidence in knowing that your phone is properly backed up in the event of it breaking or crashing. Just like the Samsung card mentioned above, these SanDisk MicroSD cards read and write data at exceptional speeds. Both of the MicroSD cards are classified as “Class 10” in their speed category, which is what you would want to look for if you do think that having the fastest card will be a benefit as you record in 4k UHD.

Many of us end up storing valuable information on these convenient little storage devices. Photographs of our big life events might be stored on this MicroSD card, or maybe loads of documents related to your work. Either way, it is important to think about the quality of the card you are saving these files on. Like with most things, the cheapest options are not always the best when it comes to a memory storage device. Simply put, if the device fails, you lose all the pictures, videos, documents and any other bit of data that might have been stored on it. This is an unlikely event, but it can be mitigated through the use of proper back-ups and by ensuring that you use memory cards with good quality-control in their manufacturing process.

To ensure you have your files backed up, you can choose from any number of options, you can easily use a second MicroSD card or save the data to a cloud service of your choice, alternatively, you can save the files to your computer or an external hard drive. Any way you go about it, having the files stored in two or three different locations is the safest way to make sure you don’t lose your precious memories and data. As to the quality of the MicroSD card itself, look to the manufacturers to see if they stand by their product. The Samsung MicroSD Memory Card lineup comes with a 10-year warranty, which can be taken as a bold statement of their confidence in the cards. SanDisk cards go one step farther by offering lifetime guarantees on their MicroSD cards.

The MicroSD Card Buying Guide

  • Be sure your MicroSD card is compatible with the device or devices that you intend to use it for. There will be a list of compatible devices in the website’s description of most MicroSD cards. This will help make sure that you don’t run into any issues when setting up your new memory card.

“To get optimal performance, especially when storing video and photography – you will want to use a minimum of a Class 10 microSD card with a smartphone,” Thornberg recommends. “For a DSLR camera, use a minimum Class 10 microSD card. For best performance, consider using a UHS1 or UHS3 class. When doing HD video work, a v-series class of microSD card will allow you the best experience in regards to saving and working with HD video. These include V6, V10, V30, V60 and V90.”

  • Formatting the card to an exFAT format rather than FAT32 is a simple process that should be done with most MicroSD cards upon initial purchase. This might sound daunting, but it’s usually a straightforward process and you can find videos online that will walk you through the process step-by-step so you can be confident you are doing it correctly.
  • The older FAT32 format of MicroSD cards will not allow file sizes of greater than 4 GB to be transferred to or from the card. When you are taking 4k UHD video footage with your camera or phone, a video file size could very well be greater than the 4 GB limit that the FAT32 formatting will allow. Without getting into too much gory tech talk, the knowledge you need to know is that exFAT is the formatting that most people want and that will give you the best user experience with your new MicroSD card.