Top critical review
Great read speeds, and acceptable write speeds
Reviewed in the United States on October 28, 2016
I purchased this micro SD SD card a few days ago, mainly for my smartphone (Axon 7), mainly for storing bulk data, and 4K video.
Performance: For my tests, I am using a UHS 1 USB 3.0 card reader, as it supports the full read and write speeds available in the UHS-1 standard.
For a more realistic performance review, I do a 100% fill, as with some lower quality cards, they may offer high initial speeds, but what happens to some, is that the write speeds may drop by up to 50% once all of the NAND is dirty (around 25-50% filled); this product does not have this issue.
Even if you do not care about the performance, I recommend that you always do a 100% fill on any flash storage that you buy, as the one thing counterfeits are unable to do, is offer consistent write speeds for the entire length of the drive.
The performance is very consistent for TLC NAND storage, with it largely able to remain close to its 20MB/s advertised on the packaging for the entire length of the card (100% fill). This one only has a marginal difference as the drive fills, which points to the NAND being fast enough saturate the storage controller while writing directly to dirty TLC flash. This means that even when the drive is mostly filled, performance will be similar to how it is when empty (only marginally slower).
Read speeds averaged 81.9MB/s, with a minimum of 77.6MB/s, and a maximum of 83.4MB/s
Write speeds averaged 20.7MB/s with a maximum of 22.3MB/s, and a minimum of 18MB/s
Those occasional changes in write speeds are due to the TLC flash being used.
After performing my 100% read and write, I then proceeded to format the card suing my phone, and then transfer some data to the card (23GB of music, photos, and videos). I then ran a benchmark using crystal disk mark. This is to more accurately represent the type of performance that the user will see when there are a bunch of files on the card already, since that is the state that the card will be in for much of its service life.
Performance for all flash memory drops slightly when data is already on the drive, thus I feel this will better represent the experience that the user will have on a day to day basis.
For smaller bursts of writes as done in crystal disk mark, we can see that it is able to exceed its advertised write speeds by a larger amount, while read speeds remained slightly lower than the 80MB/s rating. 4K reads and writes are comparable to many other cards in this price range, and the only real takeaway from this is that these cards should not be used to store applications which rely heavily on 4K reads and writes, as even the fastest UHS 1 cards, will still only offer a tiny fraction of the 4K random performance of even the eMMC NAND found in modern low end smartphones.
Overall, I am satisfied with my purchase, and would recommend the card to anyone looking for some extra bulk storage for their smartphones, as well as any netbooks. The performance is good enough for capturing 4K video. With ample space, there is no need to compromise on the quality of the video you record, the music you save to your device, or the videos you store on your device.
The card was working great for a while, and offered good enough write speeds and IOPS to ensure that the camera in the phone would not have to wait on the card, but then the card decided to fail in a very annoying way. It seems that when the card feels that it is having any issue, it permanently places its self in a read-only mode. When this happens, the card cannot be formatted, and files cannot be erased from the card.
To make matters worst, the card has to be mailed in for an RMA like that (not the best if you have a CWM backup of your device on the card).
Overall, I am currently going through the RMA process with them, and will see if the replacement card runs into any issue.
Overall, this is the first model of micro SD card that I have ever experienced failing.
I received my replacement card, I will keep an eye on how the reliability turns out for the replacement.
I also uploaded some ATTO benchmark results for the card.