A few weeks ago I decided that I would like to have some thumb drives that were so cheap that I could just hand them to someone and not worry about getting them back. To that end, I went to eBay and bought ten 4GB USB thumb drives for $3.85 each from a Chinese vendor
They were listed as 8MB/s write, 10MB/s read. When they arrived I decided I’d better test them, and it’s a good thing I did.
I used the programs h2testw and chkflsh for testing. This takes a while for full testing. Results:
2.3MB/s write instead of the claimed 8, and 5 of the 10 thumb drives had persistent data errors, corrupting data that was written to them.
Since I’ve never conducted testing of flash memory before, I decided to check everything I had. I discovered that two of the three PQI 2GB MicroSD cards that I had in my memory card pouch were totally dead, I’m RMAing them. Also I have a “JOGR” 8GB thumb drive which is glacially slow and has a persistent I/O error at a certain spot – I’m just tossing that. Apart from that, I had no problems. I have a Patriot thumb drive, several 2GB microSDs, an 8, a 16 and two 32GB microSDs and two 16GB SD cards that all test OK.
The eBay vendor says that he’ll refund me for the 5 defective 4GB sticks. We shall see.
I still want a fistful of thumb drives, but I think I’m going to go down to Costco and pick up a 10 pack of Kingston 8GB sticks for $65 rather than “deal” shopping. Memory devices are too important, and name brand ones are not that much more expensive than cheapos, to take the risk.
My advice is to pick up chkflsh here and use it on new or old flash drives. It can take a couple of hours for a quick test and up to a day for a comprehensive test; a quick test is probably fine. One thing – if you want to test drives > 4GB, you’ll need to format them NTFS first as it writes one big test file and under FAT32 a single file can’t be bigger than 4GB. You’ll probably want to format it back to FAT32 again before using it since NTFS has some disadvantages when it comes to USB thumb drives.