SD cards come in different speed classes which denote their minimum guaranteed speeds. The most common classes are Class 4, Class 6, Class 10 and UHS Class 1. Each speed class has a minimum read and write speed specified in megabytes per second (MB/s). Higher speed classes can transfer data faster which is useful for certain applications like 4K video recording. However, higher class SD cards also tend to be more expensive. This article will compare Class 4 and Class 10 SD cards in detail to help you decide which is better for your needs.
What is an SD Card Speed Class?
SD card speed classes were introduced by the SD Association to standardize the minimum performance ratings for SD cards. The speed class is denoted by a number inside a circle symbol on the card. For example, Class 10 cards will have “10” written inside the circle. The classes currently defined are:
- Class 2 – Minimum write speed of 2 MB/s
- Class 4 – Minimum write speed of 4 MB/s
- Class 6 – Minimum write speed of 6 MB/s
- Class 10 – Minimum write speed of 10 MB/s
- UHS Class 1 – Minimum write speed of 10 MB/s
- UHS Class 3 – Minimum write speed of 30 MB/s
The speed class only denotes the minimum sustained write speed. Both read and write speeds are generally higher than this. We will look at typical speeds later in the article. First let’s understand more about the common SD card classes.
Overview of Class 4 and Class 10
Class 4 and Class 10 are two of the most popular SD card speed classes used in consumer devices like phones, tablets and digital cameras. Here is a brief overview comparing them:
Class 4 SD Cards
- Minimum sustained write speed of 4 MB/s
- Typically have read speeds of 10-20 MB/s
- Maximum capacity up to 32GB
- Cheaper pricing per GB
- Suitable for standard definition video recording
Class 10 SD Cards
- Minimum sustained write speed of 10 MB/s
- Typically have read speeds of 20-30 MB/s
- Higher maximum capacities up to 512GB
- More expensive per GB
- Ideal for full HD and 4K video recording
As you can see, the main advantages of Class 10 cards are their faster minimum write speed and support for higher storage capacities. However, they are more expensive than equivalently sized Class 4 cards. Next, let’s look at the typical real-world speeds you can expect.
Real-World Speed Comparison
While Class 4 and Class 10 cards have a minimum write speed of 4MB/s and 10MB/s respectively, their actual read/write speeds are often higher depending on factors like:
- Quality of NAND flash chips used
- Controller used in the SD card
- Brand and model of SD card
Here are some real-world read and write speeds you can expect from Class 4 and Class 10 cards based on benchmarks:
Class 4 SD Card Speeds
- Read speed – 15-30 MB/s
- Write speed – 5-15 MB/s
Class 10 SD Card Speeds
- Read speed – 20-40 MB/s
- Write speed – 10-25 MB/s
As you can see, Class 10 cards are typically about twice as fast as Class 4 cards in real-world usage. The higher speeds of Class 10 make them better suited for recording full HD or 4K videos.
Price Comparison
Pricing is an important factor to consider when choosing between Class 4 and Class 10 SD cards. As a general rule, Class 10 cards will be more expensive than Class 4 cards of the same storage capacity. Here are some typical price comparisons:
| SD Card Capacity | Class 4 Price | Class 10 Price |
|---|---|---|
| 16GB | $5 – $10 | $10 – $15 |
| 32GB | $10 – $15 | $15 – $25 |
| 64GB | – | $25 – $40 |
| 128GB | – | $40 – $80 |
As you go up in storage capacity, the price difference between Class 4 and Class 10 widens. For example, 64GB and 128GB capacities are only available in Class 10 cards. Overall Class 10 cards typically cost about 1.5x to 2x more than equivalent Class 4 SD cards.
Which Devices Support Each Class?
Most consumer devices like DSLR cameras, smartphones and tablets support both Class 4 and Class 10 SD cards. However, some premium cameras may specifically require a Class 10 SD card for shooting high resolution videos. Older devices generally support up to Class 4 while newer models support up to Class 10.
Here are some device-specific requirements:
Devices that only support up to Class 4 SD cards
- Budget point and shoot cameras
- SD card readers and USB hubs with older controllers
- Older laptops and PCs
Devices that support Class 10 SD cards
- DSLR and mirrorless cameras for HD and 4K video
- Higher-end point and shoot cameras for HD video
- Smartphones released in the last 2-3 years
- Mid-range and high-end tablets
- Higher speed SD card readers
So in most cases, buying a Class 10 card will provide compatibility with the widest range of devices. Only some older or budget devices may not be able to utilize the faster speeds of Class 10 cards.
Which is Better for Gaming?
SD cards can be used to expand storage on gaming consoles like the Nintendo Switch. For gaming purposes, Class 10 SD cards are better than Class 4 due to their faster speeds.
Class 10 SD cards give you shorter load times for games stored on the card. The faster write speed also reduces lag and frame drops when the console is saving data or installing games. Most current generation consoles like the PS5, Xbox Series X and Nintendo Switch support up to Class 10 SD cards.
So in summary, Class 10 SD cards are the better choice for gaming due to their faster read and write speeds. The higher cost is worth it for a better overall gaming experience.
Lifespan and Durability
In general Class 10 SD cards are built with higher grade NAND flash memory chips compared to Class 4. This improves their lifespan and durability under frequent writes. Here are some lifespan estimates based on usage:
Class 4 SD Card
- Lifespan of 5-10 years with light usage (a few GB written per day)
- 3-5 years lifespan with heavier usage (10+ GB written per day)
Class 10 SD Card
- Lifespan of 10-15 years with light usage
- 5-10 years with heavier daily usage
So you can expect Class 10 cards to outlast Class 4 by 2-3x under equivalent workloads. This is because of their more advanced NAND chips and memory controllers. Overall Class 10 SD cards are more durable for long-term usage.
Which is Better for Cameras?
For use in cameras, Class 10 SD cards are generally recommended over Class 4. Here are some benefits of using Class 10 in digital cameras:
- Faster shot-to-shot times and preview in between bursts
- Improved buffer clearing to take more shots continuously in burst mode
- Better 4K and HD video recording and preview
- Faster transfer of photos and videos to your computer
The faster speeds of Class 10 cards allow your camera to operate more responsively. Lower end Class 4 cards may sometimes bottleneck the camera, especially for transfer of high resolution photos and 4K video footage.
Most mid-range and high-end cameras require Class 10 cards for shooting 4K video. Budget cameras are okay with Class 4 for lower resolution videos. But Class 10 will provide the best experience overall.
Which is Better for Smartphones?
For smartphones, either Class 4 or Class 10 SD cards will work fine in most cases. Phones do not require very fast SD card speeds, unless recording 4K video. Some differences when using SD cards in smartphones:
- Class 4 is sufficient for music, photos and apps
- Class 10 better for HD/4K videos and gaming
- Faster speeds of Class 10 give slightly faster app loading and file transfers
So if your usage is only basic like music and photos, Class 4 should work reasonably well to save some money. But investing in a Class 10 card is recommended if you intend to record a lot of HD/4K video or play games. The Class 10 card will give you better performance when transferring large files like videos and games.
Conclusion
To conclude, Class 10 SD cards are better than Class 4 in most cases if your device supports it. The faster speeds of Class 10 make them ideal for HD and 4K video recording as well as gaming usage. They are also more future proof as devices continue getting faster.
However, Class 4 SD cards can still be a good choice for light usage like photos and music if you want to save some money. Just ensure your device supports the slower Class 4 speeds.
With their better performance, lifespan and wider device support, Class 10 SD cards are the recommended choice for most users. The slightly higher price is worth it for the speed boost you get with Class 10 cards. If you do decide to go with Class 4 to save money, get it from reputable brands to ensure compliance with the rated speeds.