SD cards are tiny flash memory cards or storage devices designed for high-capacity memory for various portable devices such as car navigation systems, mobiles, digital cameras, digital video camcorders, and computers.

SD cards offer excellent compatibility with many electronic devices. They make the transfer of data from one device to another extremely convenient.

Buying the correct SD card as per your needs is essential. You need to check the storage capacity, the speed class and the physical size. It is crucial to purchase the right SD card also to avoid any gear malfunctions or worse, data loss.

Keeping all the things I mentioned above in mind, U3 offers more in terms of storage capacity, speed class and video class in comparison to U1.

This article features a detailed comparison between the SD cards U1 and U3. So let’s get started.

LONDISK 4K 64GB U3 Class 10 Microsd Memory Card for Phone/Tablet, Free Adapter (U3 64gb)

Micro SD card UHS-1

Faster SDXC memory cards have the Ultra high-speed rating represented by a number inside the letter “U”. U1 means the speed rating is 10 MBs.

This card provides a fast transfer speed that can rate up to 104 MBs.

The UHS-1 card was primarily used by SanDisk which greatly increased the transfer speeds. As of now, the UHS-1 is widely used for many micro SDHC and micro SDXC cards such as the SanDisk Ultra SD UHS-1 card.

Micro SD card UHS-3

UHS-3 adds a second row of pins. It provides a higher transfer speed that can rate up to 312 MBs.

The design of UHS-3 is with two lanes and LVDS technology, which significantly improves the SD card performance.

It also utilizes a QR function, also called quick recovery to optimize power management, which in turn helps the SD card reduce its transition time from dormant to active.

Since it can optimize the power consumption of a camera, the UHS-iii becomes very suitable for shooting time-lapse or extended videos.

Difference Between Micro SD U1 vs U3

UHS speed class

Two Ultra high-speed memory classes are more common now – U1 and U3. But, many of the high-end cameras need at least a U3 for many of the functions. Let us compare them and see which Micro SD card is your ideal choice.

When comparing U1 vs U3, the main difference between UHS-i class 1 and class 3 cards is that the UHS-i class has a write speed of 10 MB and class 3 has a write speed of 30 MB.

This is a significant difference and especially critical when recording large amounts of data rapidly, such as recording a 4K video.

If you are shooting a small sensor, or just street shooting or portraits, the speed may not matter much.

UHS bus

Apart from the UHS speed class, there is another thing called as UHS bus. UHS bus type is the roman numeral seen on the front of the card. The UHS bus refers to how the data is transferred between the card pins and the connector of the host device.

UHS bus will be either UHS-i, UHS-ii or UHS-iii with the maximum theoretical transfer rates of

170 MBs, 312 MBs and 624 MBs. However, the UHS bus strictly refers to the clock speed of the card and not the transfer rate.

So when you compare UHS-1 and UHS-3, UHS-3 is four times faster than UHS-1, but only in those devices that support the extra pins.

UHS-1 and UHS- 3 both have a single row of pins on the back of the card, which means that the data transfer speed can reach about 100 MBs and 400 MBs.

However, the UHS-3 card has a second row of pins added on the back of the card, which indicates that UHS-3 has a faster transfer speed.

A point to note is that UHS-1 and UHS -3 both can have either a UHS bus type of UHS-i, UHS-ii or UHS-iii.


While purchasing a new Micro SD card, storage is also an important factor to consider. The U3 SD card has more storage available when compared to the U1.

The U1 Micro SD card capacity range from 16 GB to 512 GB. On the other hand, the U3 offers a capacity from a minimum size of 16 GB to a maximum size of 1 TB.

Hence, the difference between U1 or U3 specifications, U3 are more suitable for individuals who want to store large video hour-long footage.

Video speed class

Video speed class is another important feature when comparing U3 vs U1. On the face of the SD card, you will see the letter “V” plus the roman icon number – the symbol that represents “video speed class”.

The U1 SD cards do not have the video speed class feature on the top of the card. So it becomes hard to identify the exact video speed class of this card.

The U3 SD card has the “V” icon with the number 30 alongside it on the top of the card. Hence, the U3 Micro SD card provides more options for video recording when compared to the U1 model.

The V30 icon indicates that you can easily record an HD video at 30 Mbps without dropping a single frame. This function is only available on the SDXC cards as of now.

The video speed class was created to enable higher video resolution and recording features, such as multiple video streams, 360-degree capture, VR content and 4K or 8K resolution videos.

There are five ratings for video speed class:

V6 – Video speed class 6 with a minimum write speed of 5 Mb per second.

V10 – The video speeds class 10 with a minimum write speed of 10 Mb per second.

V30 – The video speed is 30 with a write speed of 30 Mb per second.

V60 – The video speed is 60 with a write speed of 60 Mb per second.

V90 – The video speed is 90 with a write speed of 90 Mb per second.

This feature is unique because it is capable of utilising both the UHS-1 and UHS-2 bus interfaces.

The V6 to V90 speed class memory cards can use the UHS-ii bus interface, while the UHS-i bus interface can only support V6 to V30 speed class memory cards.

Other SD card or Micro SD card speed rating

There are various ratings within the speed class, which are denoted with the symbol “C”. The different classes the memory card come in are –

C2 – Class 2 with a minimum write speed of 2 Mb per second.

C4 – Class 4 with a minimum write speed of 4 Mb per second.

C6 – Class 6 with a minimum write speed of 6 Mb per second.

C10 – Class 10 with a minimum write speed of 10 Mb per second.

The C2 is the lowest speed class while C10 is the industry standard. In present times, newer hardware devices require newer speed classes with higher speeds and capabilities.

C10 is usually the minimum speed class requirement for most hardware devices made today and is the most shipped memory card on the market.

About SD Card speed

Every SD card has a speed class labelled on the front side. These “classes” determine the speed of the memory card. The SD card speed can read and write at speeds of 12.5 MBs by default.

You will need a faster memory card if you are shooting RAW or an HD video. If you are just planning to store a couple of photos or documents, you do not need a faster memory card.

With the development of SD cards, the Ultra high-speed class is now available on lots of SDXC and SDHC micro sd cards.

A faster memory card will support larger files and be quicker when processing them. So if you are shooting in 4K or RAW files, you will need an SD card equally as powerful to keep up with all these files.

How to choose an SD card

There are many types of SD cards – SD, SDHC and SDXC. As SD cards have been known to shrink in size over these past years, the “SD” card can be considered a “full size” card.

It is used in most modern digital cameras and nearly all laptops come with an equipped SD card reader slot.

SDHC stands for “Secure digital high capacity”. This type was introduced to cover SD cards with a capacity above 2 GB and below 32 GB.

SDXC stands for “Secure digital eXtra capacity”, which goes far beyond 32 GB in size.

It is worth noting that all these SD card types physically look the same, therefore they will all fit in a regular SD card slot.

What you want to take care of is to buy an SD card depending on the device you’re looking to use them in and if they are compatible, otherwise, problems might arise.


The U3 Micro SD card is better than the U1 card from the aspect of transfer speed, video speed class and Ultra high-speed class. So between U1 or U3, U3 is the ideal choice for all the users.

UHS I vs Class 10 Cards

What is UHS U3?

UHS is the minimum sustained writing performance for recording video, and that for the u3 sd card is three.

Is UHS 1 the same as Class 10?

Yes, UHS 1 is an equivalent of class 10 since they have the same minimum data transfer speed of 10mbps. The technical specifications are also identical.

Is U3 better than U1?

Yes, U3 is better than U1 since it has some features which the other model does not have. It can, therefore, perform more functions making it the better choice.