I have seen many people report that this Micro SD is not reporting the correct dimensions and I had the same problem. However, I tried the micro SD card in my phone and found that after backing up, it is actually 128GB, 115.64GB. I then tried several other adapters for my PC and found that the adapter was the culprit and not the card itself. I tried this with a Sandisk SD card and got the same errors until I put it in my working adapter or my put the phone in. The speed is decent, although keep in mind that other reviewers may not be aware that there are many factors that affect the speed of this device. Are you using a USB 2.0 or 3.0 port? Is your USB 2.0 or 3.0 adapter compatible? What files are you transferring? When transferring 25GB files, the speed for me was a steady 10MB/s (with spikes) via the USB 2.0 adapter in the USB 3.0 slot, which is generally what lower speed cards should do. So if the map doesn't show its full size, try using your phone or another adapter. The cheap adapters I used were able to report accurate sizes for 32GB or less, but this caused problems with 64GB and larger cards. Also, don't just run a test and find out the speed of the card. Different files affect performance and USB versions affect performance and the benchmark does not replace actually using the device to determine its speed.
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