You should be alert when you are shopping online for memory cards. Even Amazon is guilty of shipping fake SD cards to buyers, not to mention other e-commerce sites like eBay and AliExpress.
Read this: Watch Out for Fake SD Cards - How to Tell If an SD Card is Fake
Different types of fake SD or microSD cards
Reduced read/write speed. The read/write speed is a lot slower than advertised.
Smaller capacity. This is the most common type of fake memory card. The card will report a 512GB capacity to your computer or other digital devices, but in fact, it only has a 16GB memory cell. It won't allow you to store more data and might cause card corruption if you do.
Fake brand. Some memory cards are branded by well-known companies and sold at a premium price, but actually, these companies don't manufacture any memory cards. For example, any SD cards with a HUAWEI brand are fake.
Unrealistic capacity. Most microSD cards you can get on the market has the largest capacity of 512GB and only a few specific microSD cards can have a capacity of 1TB. By now, if you see any microSD cards with a size of 1.5TB, 2TB, or more, it is very likely that they are fake.
How to test a fake SD card
It is easy to fall into a trap when you see the mind-blowing deals on memory cards. You can easily identify a fake SD card by its fake brand or unrealistic capacity, but how to tell the capacity and read/write speed is fake can't be done until you have the card.
How to test the read/write speed of a possibly fake SD card
Make sure your interface and card reader are both fast enough to allow the SD card to run at the highest speeds. You can check the read/write speed by copying a large video file (1-2GB) to the card to see if it is unacceptably slow. Or you can use a free tool to check the SD card reading or writing speed on a PC.
How to test the real capacity of a fake SD card
FakeFlashTest is for testing the actual memory size of USB flash drives and SD cards. This simple tool contains two tests - Quick Size Test to report the actual capacity and Test Empty Space to tell the remaining free space.
However, these tests are destructive and will probably cause permanent data loss. If possible, back up your files before testing your microSD or SD card.
If you find your SD cards are fake, you should return them and get a full refund. Also, do other people a favor by reporting the seller to the e-commerce platform's customer service or sharing your experience on forums.
Shame on scammers.