SD cards, or Secure Digital cards, are non-volatile storage devices used in portable devices like cameras, mobile phones, and tablets (SD Association). They are commonly used to store media like photos, videos, and music. The speed of an SD card determines how fast you can read and write data to the card. This is measured by read and write speeds, which are indicated by speed classes like Class 10 and UHS 3.
This article examines whether a 120MB/s SD card speed is considered good. We’ll provide an overview of SD card speeds, common use cases and requirements, benchmarks, and recommendations for selecting the right SD card speed for your needs.
SD Card Basics
SD cards were first introduced in 1999 as a joint effort between SanDisk, Panasonic (Matsushita Electric), and Toshiba as an improvement over MultiMediaCards (MMC). The SD format was based on MMC cards and aimed to offer greater capacity in a similarly sized package [1]. Since then, SD cards have become one of the most widely used memory card formats.
There are several sizes and types of SD cards, including the original SD format, miniSD, microSD, SDHC (high capacity), and SDXC (extended capacity). The microSD card has become especially popular as removable storage for smartphones, tablets, and other small devices [2]. SD cards typically range from 1GB to 2TB in capacity.
Today, SD cards are most commonly used in digital cameras as storage for photos and videos. They are also frequently used in handheld gaming devices, smartphones, tablets, and audio players to store media files and apps. The small size and rewritability make them convenient removable storage.
Read and Write Speeds
SD cards have speed ratings that indicate their maximum read and write speeds. Read speed is how fast data can be read from the card, while write speed is how fast data can be written onto the card. SD cards use speed classes to specify the minimum guaranteed speeds.
Some common speed classes are:
- Class 2 – Minimum write speed of 2 MB/s
- Class 4 – Minimum write speed of 4 MB/s
- Class 10 – Minimum write speed of 10 MB/s
- UHS Speed Class 1 (U1) – Minimum write speed of 10 MB/s
- UHS Speed Class 3 (U3) – Minimum write speed of 30 MB/s
- Video Speed Class 10 (V10) – Minimum write speed of 10 MB/s
- Video Speed Class 30 (V30) – Minimum write speed of 30 MB/s
- Video Speed Class 60 (V60) – Minimum write speed of 60 MB/s
- Video Speed Class 90 (V90) – Minimum write speed of 90 MB/s
Higher speed classes allow for faster read/write speeds, which is beneficial for recording and transferring large files like high resolution photos and videos. Most basic SD cards today are Class 10, while high performance cards are U3, V30 or above.
According to Kingston, typical real-world speeds for different classes are:
- Class 2: 2-5 MB/s write, 10-20 MB/s read
- Class 4: 3-8 MB/s write, 10-20 MB/s read
- Class 10: 10-30 MB/s write, 20-40 MB/s read
- U3: 30-90 MB/s write, 50-100 MB/s read
- V30: 30-100 MB/s write, 50-150 MB/s read
- V60: 60-150 MB/s write, 90-250 MB/s read
- V90: 90-250 MB/s write, 150-350 MB/s read
120MB/s Speed
SD cards with read and write speeds around 120MB/s are considered relatively fast and can support high bitrate 4K video recording and other bandwidth-intensive uses. These speeds are achievable with higher-end SD cards that support the UHS-I interface.
For example, the SanDisk 128GB Ultra SDXC UHS-I Memory Card is rated for 120MB/s read and write speeds. In benchmarks, these cards can reach speeds of 80-100MB/s sequential reads and 50-70MB/s sequential writes, with even faster speeds for shorter burst workflows.
According to user reports on forums like Reddit, real-world performance of 120MB/s cards in devices like the Steam Deck can vary based on factors like the SD card reader and interface. Speeds may be lower than marketing claims. So it’s important to study independent benchmarks when selecting a specific SD card model.
While 120MB/s cards offer a nice boost over slower cards, even faster read/write speeds are possible with higher-end SD cards supporting UHS-II or UHS-III interfaces. But for many users, 120MB/s UHS-I cards strike a good balance of speed and affordability.
Use Cases and Requirements
High-speed SD cards with read/write speeds of 120MB/s are best suited for devices and applications that need to transfer large files quickly. According to Kingston, 120MB/s cards are recommended for 4K video recording, high-resolution photos, gaming applications, and running programs or apps directly from the SD card.
Devices that can take advantage of 120MB/s SD cards include high-end DSLR and mirrorless cameras, drones, Android smartphones, and the Nintendo Switch. The fast read/write speeds allow you to quickly save high-resolution photos and videos to the card without being bottlenecked. It also reduces the risk of losing data if the camera buffer fills up.
For smartphones, a 120MB/s card allows you to launch apps faster if they are installed directly on the SD card. Downloading and transferring files to and from the card is also faster. According to Wired, you may not need the top speeds for routine tasks, but the performance boost is useful for managing and editing media.
In most cases, high speed is not absolutely necessary, but provides a performance advantage over slower cards. The speed boost is most useful for power users who frequently work with high resolution media files.
Alternatives
While SD cards with speeds up to 120MB/s are fast, there are even faster options available. Top-of-the-line SD cards can reach speeds up to 300MB/s with the latest SD Express standard. These ultra high-speed cards allow for 8K video recording and faster transfer speeds, but come at a premium price.
On the lower end, Class 2 SD cards with minimum write speeds of 2MB/s are sufficient for basic tasks like viewing photos. Class 4 (4MB/s) and Class 6 (6MB/s) cards can be used for 720p video recording. However, for full HD 1080p video or high resolution photos, Class 10 cards with minimum 10MB/s write speeds are recommended.
Besides different speed grade SD cards, there are also other storage media options to consider:
- CompactFlash (CF) cards are larger in physical size and commonly used in high-end DSLR cameras. They range from basic speeds up to 1066x cards with over 1GB/s transfer rates.
- USB flash drives use the universal USB interface and provide portable storage for computers and other devices. Models with USB 3.0/3.1 offer speeds over 300MB/s.
- External SSD drives connect via USB and can offer transfer rates up to 10 Gb/s with USB 3.2 Gen 2×2.
When choosing storage, it depends on the device capabilities, performance needs, size constraints and budget. While 120MB/s SD cards offer a good middle ground, faster and slower alternatives exist for different use cases.
Factors for Card Selection
There are several key factors to consider when selecting an SD card:
- Price – SD cards range greatly in price based on factors like capacity, speed, and brand. Determine your budget and look for good value.
- Capacity – The storage capacity needed depends on your intended use and device. For example, 4K video requires more storage than photos. Choose a capacity adequate for your needs.
- Brand reliability – Stick with major brands like SanDisk, Samsung, Sony, Lexar, etc. for proven reliability and performance.[1]
- Speed rating – Faster cards have higher read/write speeds. This improves performance for recording video, burst shooting photos, etc.[2]
- Endurance – Cards with high endurance ratings can withstand more read/write cycles before failure, important for long-term usage.
- Compatibility – Ensure the card works with your device before purchasing.
Considering these key factors will help select the right SD card for your needs and budget.
Recommendations
Overall, a 120MB/s SD card offers great performance for most use cases today. However, it’s important to consider your specific needs when selecting an SD card. Here are some guidelines:
A 120MB/s card is recommended for:
- 4K video recording – Writing high resolution video requires fast write speeds. 120MB/s can support smooth 4K recording.
- High resolution photos – Like video, high res images require more data to be written quickly. 120MB/s is fast enough for most cameras.
- Devices with fast processors – For smartphones and tablets with fast processors, a 120MB/s card can keep up when saving photos and apps.
When a faster card may be required:
- Professional/high frame rate 4K video – Videographers shooting 60fps or 120fps 4K may want an even faster card.
- Raw high resolution photos in burst mode – Taking many 20+MP raw images in fast sequence demands fast write speeds.
- High performance devices – Some very fast tablets and phones can benefit from cards faster than 120MB/s.
The right card depends on your use case. Consider the resolution of your camera or device capabilities. Don’t pay for higher speeds you can’t take advantage of. But for most users today, 120MB/s hits the sweet spot of fast performance without getting too expensive.
Benchmark Results
Real-world testing shows that 120MB/s cards can achieve read speeds around 90-100MB/s and write speeds of 60-80MB/s depending on the specific card and testing conditions (Source: https://www.cameramemoryspeed.com/reviews/micro-sd-cards/). While maximum speeds may reach 120MB/s in optimal conditions, average speeds are typically lower.
For example, the SanDisk Extreme 120MB/s microSD card was tested by Camera Memory Speed and achieved sequential read speeds of 92MB/s and write speeds of 60MB/s (Source: https://www.cameramemoryspeed.com/reviews/micro-sd-cards/). The Lexar 120MB/s card reached 92MB/s read and 79MB/s write in the same tests.
Cards with rated speeds of 120MB/s provide a real-world performance boost over slower cards in the 10-30MB/s or 45-90MB/s range. However, diminishing returns set in after around 90-100MB/s for many use cases. Unless peak throughput is required, 120MB/s cards offer limited practical benefit over slightly slower options (Source: https://www.reddit.com/r/SteamDeck/comments/vopisc/if_money_isnt_a_factor_what_is_the_fastestno/).
Conclusion
In summary, a 120MB/s SD card offers very fast read and write speeds that outperform lower speed classes. This makes it well-suited for 4K video recording, burst photo shooting, and other demanding tasks. The speed provides a seamless user experience with quick transfer times.
However, not everyone needs a blazing fast 120MB/s card. For casual users, a lower speed class may suffice at a cheaper price point. When shopping for an SD card, consider your particular use case and equipment capabilities to determine if a 120MB/s card is necessary.
For serious content creators working with high resolution media, the extra performance of a UHS-II or UHS-III card is advisable. But 120MB/s remains a significant upgrade from standard SD cards. Overall, it hits a sweet spot between price and speed that will satisfy many power users.