128GB SanDisk Ultra A1 microSD Review

SanDisk Ultra microSD is one of my favourite cards. Owning 64GB card few years back and still kicking until now. Of course, its performance is way slower compare to newer cards nowadays. 128GB SanDisk Ultra A1 microSD is the star today. It is loaded with blazing transfer speeds @ 100MB/s read and support App Performance Class 1 (A1). Does it really that fast? Let’s find out…

Special Thanks
This review is possible thanks to below companies. Be sure to check them out too…

Package Content & Design
My 128GB SanDisk Ultra A1 microSD (SDSQUAR-128G-ZN6MA) is from China directly. There are global (SDSQUAR-128G-GN6MA) and Americas (SDSQUAR-128G-AN6MA) version too. Basically, they are the same. And there are other capacities to choose – 400GB, 256GB, 200GB, 128GB, 64GB, 32GB and 16GB. Most of the microSD cards do not have lifetime warranty anymore. Same apply to SanDisk which has 10 years warranty.

Performance Result
128GB SanDisk Ultra A1 microSDXC is a class 10 UHS-I card. Not sure this is year 2017 / 2018 model. Anyway, it is the latest SanDisk Ultra series so far. And the fastest one yet. Without further ado, let’s find out its performance in details starting with CrystalDiskMark.

99 MB/s sequential reading speed! Yes, that’s maximum speed that SanDisk Ultra A1 can reach. However, sequential writing speed is way much lower at 47 MB/s only.

ATTO Disk Benchmark has the same reading speed but even lower writing speed at 27 MB/s for most transfer sizes except 128KB.

Anvil’s Storage Utilities is the best way to find out all the ability of the storage performance. You can see Input-Output access Per Second (IOPS) performance for 4K tests as well. SanDisk Ultra A1 has great IOPS for reading and almost reach A1 standard by SD Association IOPS for writing.

As for real world tests, BlackVue DR490L-2CH Dual FHD dash cam, Xiaomi Mi Action Camera 4K, Mi Sphere 360° panoramic camera, Redmi Note 4 and Galaxy Note 8 are being used. 128GB SanDisk Ultra A1 passed with flying colours. Yes, it manages to perform even on summer hot temperature on dash cam in car. And able to write up to 4K UHD 100 Mbit/s super fine quality mode on action camera (not sure about GoPro HERO6 Black).

AndroBench replaced A1 SD Benchmark on mobile test as it covers 4K IOPS. 128GB SanDisk Ultra A1 does perform up to App Performance Class 1 standard. This is great to use it as internal storage as part of Android Adoptable Storage.


  • Excellent sequential read transfer rate
  • Fast 4K IOPS rate for both read & write
  • UHS-I U1 & A1 support
  • Extreme protections
  • Decent build quality


  • Slow sequential writing speed

128GB SanDisk Ultra A1 is a budget yet performing microSD card. Loaded with fast reading speed with A1 support. Perfect to use on your dashcam, smartphone, tablet, digital camera, recorder and even drone camera. More information can be found at SanDisk Website. And buy yours at GearBest.


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