I just bought a 64Gb Sandisk Ultra SDXC (30mb/s; class 10) card from a third party seller on amazon that was 10% cheaper than amazon themselves (although the amazon version comes in “frustration free packaging”).
I wanted to verify that it was a genuine item so I used 2 benchmarking tools: http://usbflashspeed.com and h2testw. On my Dell computer (which is about 3 years old, running windows 7) and it’s original built in multicard reader, both programs were recording a write speed of between 6.9 and 7.1mb/s in all cases except the very small writes on usbflashspeed, where the speed really tailed off to almost nothing. Read speeds hovered around the 11.5mb/s mark. The card info on usbflashspeed had the card manufacturer as TEAC - do they make cards for Sandisk? So the card seemed very slow to read and write, but h2testw confirmed that the card was full 64Gb size (after all most a 3 hour write session to fill it.
Looking at pictures of the card on various sites, the write protect tab of the card looks white or very light grey, but on my actual card, it is dark grey - the same shade as the grey on the card’s label. The indent on the bottom of the card is present but appears very shallow compared to the indent you see on official photos of the card.
The card has a 13 digit serial number printed onto the reverse, in a medium grey colour, with the bottom of the lettering approximately 4mm from the base of the card and approximately 8.5mm long.
I don’t know whether the official packaging backing card is supposed to have any holographic/metallic printing or stickers, but it definitely doesn’t.
With all the above info it would seem that from a read/write perspective that I have a 64Gb class 4 or 6 card made by TEAC, unless my card reader is reading/writing slow due to a hardware/software problem?
So what does everyone think? Genuine, but my card reader isn’t up to scratch, or fake? I have class 4 cards that benchmarked faster (not much faster) than this card on the same card reader.