Recently, while staying with my parents in the US, I was persuaded to purchase a 64 gb micro SDHC card from eBay.
The price seemed too good to be true (around $20), but the seller had a good rating, and maybe the card was legitimately this size, so we ordered it, and it arrived quickly.
Then the problems began. I tried to format it to NTFS, and Windows reported the card could not be formatted, but formatting back to exFat yielded a 64 gb card!
A little digging turned up a small utility named H2testw v1.4, which is a burn in test program for SD cards. Here’s the result on this “bargain” card:
The media is likely to be defective.
1.9 GByte OK (4091392 sectors)
60.5 GByte DATA LOST (126972416 sectors)
Details:0 KByte overwritten (0 sectors)
0 KByte slightly changed (< 8 bit/sector, 0 sectors)
60.5 GByte corrupted (126972416 sectors)
0 KByte aliased memory (0 sectors)
First error at offset: 0x000000007abc0000
H2testw version 1.3
Writing speed: 8.48 MByte/s
Reading speed: 5.67 MByte/s
A little more digging turned up an article on counterfeit sd cards:
Naturally we returned the item, and the seller refunded, but they also attacked other buyers who reported the fakes.
So, my advice: Stick to a reputable seller, like Amazon, and do make sure you check the actual seller.