U3 SD Cards vs U1: What's the Difference and Detailed Comparison? (2023)

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U3 and U1 SD cards are some of the fastest SD cards made by Scandisk in recent history. The single "U" refers to a type of bus interface for memory cards. It is also important to note that you may find the acronym UHS used interchangeably with the single "U" for this class. This works so that U1 refers to UHS-1 and U3 refers to UHS-3.

U1 and U3 micro-SD cards are very popular among users, but sometimes it is not so easy to tell them apart. U3 was introduced in the market after U1, which means it has more improved and developed features. Then we do an in-depth analysis of the two memory cards and their features. What is the difference between the two, and which one is better? Both micro-SD cards are sold in online and brick-and-mortar stores and, being UHS versions, are known for their fast speeds.

To effectively understand these micro-SD cards, you need to have a general understanding of SD card speed. Here's a brief explanation of exactly what speed class means when it comes to SD memory cards.

table of contents to hide

  1. 1 speed class
    1. 1.1 UHS-1 Micro SD card
    2. 1.2 UHS-3 Micro SD card
  2. 2Differences and similarities between U1 and U3
    1. 2.1 Capacity
    2. 2.2 Data transfer rate
    3. 2.3UHS bus speed
    4. 2.4UHS Speed ​​Class
    5. 2.5 Video Speed ​​Lesson
  3. 3U3 or U1, which is better?
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speed class

There are significant disparities in memory access speeds depending on the manufacturer and brand of SD memory card. Fluctuating and inconsistent speeds make it difficult to choose which memory cards can efficiently record streaming content. Video recording requires a constant, minimum recording speed to produce the best results. This helps reduce and prevent "frame drops" during recording to ensure smooth playback. An SD membership defines several speed class standards to meet the growing demand for rich video quality recordings. There are speed card symbols on the market suitable for hosting and product cards. These symbols allow users to make the best decision regarding the best combinations for reliable or flawless recording. There are three types of speed indications:

  • speed class
  • UHS speed class
  • Video lessons

Speed ​​class symbols with a number indicate the minimum write speed. This mostly comes with camcorders, video recorders and other devices with video recording capabilities. The speed classes defined by the SD association are classes 2, 4, 6 and 10. Class 10 can be classified with the high speed bus IF product family.

When it comes to the bus mode, it is essential to use a bus mode that does not affect the memory write speed as it is fast enough. C10 is used in high speed or faster mode, while theU1 and U3 are used in SDR50/DDR50 or faster.

The video speed class was created to meet the high demand for high-quality, high-resolution 4K8K video recording. This class also has a special function to support next generation flash memory such as 3D NAND. As it supports HD speed (2K), it is possible to integrate it into the video class from now on.

By choosing the best match between host and speed class card, users can find the best card for a host through a combination of speed class symbols. To do so, choose the same class symbol card or one of a higher class than the indicated host's class symbol.

UHS-1 microSD card

It was the first upgrade to the standard high-speed specification. It provides relatively fast transfer speed that can reach up to 104 Mbps. Its version 3.01 also specifies that it supports a clock frequency of 100 MHz. SanDisk has extensively used the proprietary UHS-1 extension to significantly increase transfer speeds for many SDHC and SDXC cards.

MicroSD UHS-3 card

This specification was introduced in 2017 and added a second row of pins. It also provides very high transfer speeds that can reach up to 312mbps. Furthermore, the U3 is designed with two rails and LVDS technology that significantly optimizes its performance. It also employs a newer Quick Recovery (QR) feature to improve power management, helping the card reduce idle-to-active transition time. Whether you're shooting time-lapse or extended video, this technology is a deal breaker as it improves power consumption.

Differences and similarities between U1 and U3

Many of the features of the U1 and U3 are similar, but some are fundamentally different.


Card capacity is measured in gigabytes and differs from memory card to memory card. Usually, you will notice that U3 SD card has more powers available compared to U1. For the SanDisk U1 micro-SD card, capacities range from 16GB to 512GB. The U3 SD card, on the other hand, has available capacities from a minimum of 16 GB to a maximum of 1 TB. This shows that the U3 offers more in-store options for people looking for long-term storage and ample footage.

data transfer rate

Another critical difference between the two memory cards is the data transfer speed. The U3 model offers higher transfer speeds than the U1 model. If you are interested in having a high recording and copying speed to record a 4K video, the U3 model is an ideal choice. The U1 models have a speed of 100Mbps while the U3 models have a transfer speed of 175Mbps. The U1 model can go up to 104mbps while the U3 can go up to 312mbps.

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UHS bus speed

This refers to how data is transferred between the pin on the card and the connector on the host device. Roman numerals and intervals indicate from one to three. UHS/ is on both models and uses a single row of pins on the back of the card to transfer approximately 104 Mbps. It's one of the things the cards share, and it's common to most cards as it's compatible with a variety of cameras.

UHS speed class

Although closely related to UHS bus speed, this element plays a different role and is also indicated on the face of the card. It's a number inside a U-shaped logo that indicates speed; U1 has the number one while U3 has three meanings: U3 has significantly faster speeds.

video speed class

This is a critical feature specifically for video recording and is indicated by a V icon on the card. U1 cards don't have this feature well displayed on the card, but U3 cards have the v icon with the number 30 next to it. This means that HD videos can be recorded at 30Mbps without frame loss and are only available on SDXC cards. Buying the U3 model is more advantageous for recording compared to the U1 10 model. The UHS 1 model is class 10 equivalent and has a minimum data transfer of 10 Mbps.

U3 or U1, which is better?

The U3 memory card variation proves to be superior to the U1 model as it has unique features that help it to perform more functions and hence the best option.

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dion lewis

My name is Dion Lewis. Photography is my life and I took it as my profession after graduating. I'm a professional, covering almost everything from fashion, architecture, editorial issues and corporate lifestyle. I've worked with clients like CNN, Alabama State University, Steelcase, LiveStrong and more. I'm based in Alabama. If you need my service, please don't hesitate to contact me.

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