A1 is a performance rating introduced by the SD Association to indicate the speed capabilities of microSD cards used in smartphones and tablets. A1 cards offer faster app launches, quicker file transfers, and better overall system responsiveness compared to lower-rated cards.
What Does A1 Stand For?
A1 stands for Application Performance Class 1. The A1 rating was introduced in 2016 as part of the SD Association’s SD 5.1 specification. It aims to provide a simple way for consumers to identify cards that offer faster performance in mobile devices.
Requirements for A1 Rating
To earn an A1 rating, a microSD card must meet the following speed requirements:
- Minimum random read IOPS of 1,500
- Minimum random write IOPS of 500
- Minimum sustained sequential read speed of 10MB/s
- Minimum sustained sequential write speed of 4MB/s
IOPS refers to input/output operations per second. This measures the card’s ability to handle multiple small file reads and writes rapidly. The sustained read/write speeds indicate performance for sequential transfers like reading photos or videos.
Advantages of A1 microSD Cards
Here are some of the key benefits offered by A1-rated microSD cards compared to slower cards:
- Faster app load times – The higher random read IOPS helps apps launch faster.
- Smoother gaming – Quicker reads and writes lead to better graphics rendering and less stuttering in games.
- Improved multitasking – Background tasks and file transfers happen faster thanks to higher sustained speeds.
- Better overall system responsiveness – Using an A1 card can make the phone UI and menus feel more snappy.
In essence, the A1 specification focuses on the types of access patterns seen in smartphones and tablets. This results in a more responsive, lag-free experience compared to slower UHS-I cards or plain class 10 cards.
Real-World Performance Differences
Independent benchmark tests indicate that A1 microSD cards can deliver 2-3x faster random read/write speeds compared to non-A1 cards. This translates to noticeable improvements in app load times and game launching. Here are some examples:
- The Temple Run game launched about 2 seconds faster with an A1 card compared to a slower UHS-I card in one test.
- A benchmark test showed an A1 card copying a set of image files to internal storage around 30% faster than a slower card.
- PDF files also loaded noticeably faster from an A1 card vs. a non-A1 card in side-by-side tests.
Of course, the exact performance gain will depend on your smartphone model, the specific apps being used, and other factors. But overall, A1 microSD cards deliver measurably snappier load times and response compared to lower-tier cards when used in phones.
microSD Card Speed Classes Explained
In addition to the A1 rating, microSD cards also carry standard speed class ratings like Class 10, UHS Speed Class 1, etc. Here is an overview of what these different ratings mean:
Class 2
Minimum read/write speed of 2MB/s. Too slow for anything beyond basic file storage.
Class 4
Minimum of 4MB/s read/write speed. Still quite slow but usable for basic needs.
Class 10
Minimum sequential read/write speed of 10MB/s. Became the standard for SD cards and remains a popular bare minimum speed class.
UHS Speed Class 1 (U1)
Minimum sequential read speed of 10MB/s. Meets Class 10 requirements but indicates UHS-I interface for better burst shooting and fast bus speed.
UHS Speed Class 3 (U3)
Minimum sequential read/write of 30MB/s. Only achieved by top-tier UHS-I cards. Enables 4K video recording and fast burst mode shots.
The A1 build further on UHS-I interface and aims for even faster random read/write speeds to benefit mobile devices.
Do You Need an A1 microSD Card?
Whether an A1 microSD card makes sense for you depends on a few factors:
- Device support – Your phone/tablet needs to be designed to take advantage of A1 card speeds and features.
- Usage patterns – Heavy mobile gaming, intensive multitasking, 4K video recording see the most benefit from A1 cards.
- Existing microSD card speed – Upgrading from a slower UHS-I or Class 10 card is worthwhile. If your current card is U3 rated, benefits may be small.
- Cost differential – A1 cards usually cost $5-10 more than basic UHS-I cards. Paying extra may not make sense if you won’t use the speed.
For most users, an A1 microSD card is recommended since it delivers better overall performance at a small premium. But it’s not an absolute necessity if you just need extra basic storage and won’t use apps much from the card.
Top A1 microSD Cards
Here are some of the top-rated A1 microSD cards from leading manufacturers:
| Brand | Model | Capacity | Max. Sequential Read | Max. Sequential Write |
|---|---|---|---|---|
| SanDisk | Extreme | 64GB | 100MB/s | 90MB/s |
| Samsung | EVO Plus | 128GB | 100MB/s | 90MB/s |
| Kingston | Canvas Select Plus | 32GB | 100MB/s | 85MB/s |
| PNY | Elite-X | 512GB | 100MB/s | 90MB/s |
| Lexar | 667x | 256GB | 95MB/s | 70MB/s |
These A1 cards from leading brands offer fast read/write speeds of up to 100MB/s along with strong random IOPS performance. This combination provides excellent overall performance in smartphones, tablets and other mobile devices.
How to Check if Your Phone Supports A1 SD Cards
There are a few easy ways to check if your Android phone or tablet supports microSD cards with A1 performance:
- Check your device manufacturer’s website for specifications. The product specs sheet should indicate A1 support if available.
- Look at the phone packaging or documentation for any A1 microSD card mentions or compatibility notations.
- Go into your device settings menu and find the Storage or Memory section. If it mentions support for A1 SD cards, your device is compatible.
- Contact your device manufacturer’s customer support by phone or chat and ask if your specific model works with A1 cards.
Most newer mid-range and premium Android devices support A1 storage. But it’s still a good idea to verify before buying a microSD card, especially for budget models.
How to Test Actual microSD Card Performance
To check the real-world read/write performance of a microSD card in your phone, you can use benchmark apps like:
- AndroBench – Provides sequential and random read/write speeds for storage
- SD Card Test – Measures IOPS, access time and transfer speeds
- Disk Speed Test – Quickly tests sustained read/write throughput
Run these benchmarks on your current microSD card. Then compare those results with benchmarks of a new A1-rated card. This will give you an accurate idea of the performance difference you can expect to see.
Day-to-day use is also a good indicator. If apps and games feel sluggish loading from your current card, upgrading to an A1 card is likely to provide a nice boost.
microSD Card Myths
There are some common myths and misconceptions regarding microSD cards that are worth clarifying:
Myth: Bigger capacity cards are faster
Reality: Capacity (e.g. 64GB vs 256GB) has no impact on speed class or performance. Only the controller and flash memory matter.
Myth: A1 cards won’t work in non-A1 devices
Reality: A1 cards are backwards compatible and will work in any device that takes UHS-I cards, but won’t provide A1 speeds in non-A1 devices.
Myth: A1 is the fastest microSD standard
Reality: A2 and A3 cards offer even faster sequential read/write, while V90 and V60 are optimized for 8K video recording.
Myth: More megapixels means slower card speed needed
Reality: Higher resolution photos/videos require more storage space but not necessarily faster card speeds.
Always check microSD card specs and your device compatibility rather than assuming capabilities based on partial information.
Conclusion
A1-rated microSD cards offer improved random read/write speeds compared to lower-tier UHS-I and Class 10 cards. This enables faster app launch times, better responsiveness and smoother gaming in smartphones and other mobile devices.
While not all users need the performance boost of A1, it provides a real-world difference at a small price premium. With smartphone storage demands increasing, an A1 card makes sense for most people over entry-level options.
Following the SD Association’s ratings and checking your device’s support for A1 ensures you get a compatible card that delivers fast, stutter-free performance. Brands like SanDisk, Samsung and Kingston offer reliable A1 microSD options to consider.