[REVIEW] Transcend 300S microSD Card – Class 10, U3, V30 & A1

Media and apps are getting larger and larger that carries more information and data. Even a 64GB onboard storage smartphone may not enough for certain users. microSD may be the cheapest options for storage expansion. There few rating of microSD card by the terms Speed Class, UHS Speed Class, Video Speed Class and App Rating.

People from Transcend sent us Transcend 300S microSD card with rating Class 10, U3,  V30 and A1. By the rating of V30 and A1, the Transcend 300S should able to deliver minimum 30MB/s write (V30) and 10MB/s random IOPS.

“V30” class rating is important for those who do high-speed video recording especially a lot of flagship smartphones now are capable to record in 4K. The “A1” class rating is certified the memory card is fast enough to handle apps that installed onto it instead on the internal storage. Hence you may free some internal storage by moving media and also certain apps onto the memory.


Just like other ordinary microSD card packaging with cardboard seal and it comes with a microSD to SD card size adapter.


I’ll be performing two types of benchmark test on the Transcend 300S microSD card;
1. microSD USB 3.0 Card Reader
2. Samsung Galaxy S8 Plus

USB Card Reader Test

We use CrystalDiskMark test on PC and it performs pretty much it advertised. It has sequential read speeds around 95MB/s and over 30MB/s writing which surprised me. The V30 rating specification is required to be at least 30MB/s of sequential write speed and V60 is 60MB/s, it looks like it does over the mark.

As for the random IOPS, the Transcend 300S hit more than 10MB/s on all the random 4K tests thus it rated “A1” class.

File transfers of 6GB were completed less than 2 minutes, it’s darn impressive for such a tiny card.

Smartphone Test

I’m using almost 2 years old Samsung Galaxy S8 Plus and my internal storage pretty much full as I use this device as my main camera for photos taking and video recording.

I use the AndroBench for the test and the result shows slower compared it to my PC. But overall it able to get 76.9MB/s sequential read speed and 55.9MB/s sequential write speed. The random IOPS 4K hit 10.3MB/s.

With the additional storage now I able to move all my media and even certain apps into the memory card, freeing up the internal storage.

Only certain apps that able to move into the external storage card like Instagram, Google Photos, Games and etc where you can see it in your device Settings – Apps.

I was able to free-up almost 10GB of storage after just moving the apps and gaming into the Transcend 300S. Now all the photos and videos will storage directly into the memory card to have more healthy internal storage system.

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Transcend 300S A1 microSD Card
  • Performance
  • Value


Sometimes you may wonder which memory card suitable when there are various types of rating memory card. We would highly recommend you Transcend 300S A1 microSD card that fits most usage even moving your apps into the memory card. Chances of files corruption would greatly be reduced with this capable card.

It has speedy sequential reads and writes, allowing it suitable for 4K recording and even running apps directly on the card without any issue.

With the A1 speed rating, its also meet the requirement to runs on Windows Tablets, Convertibles and Notebooks for onboard storage expansion.

Transcend 300SA1  microSD card is offers in 128GB and 256GB. You can find it at major IT mall and as well as e-commerce platforms like Lazada and Shopee.