A Closer Look

The 256 GB Kingston Class 10 UHS-I SDXC Card looks like any other SD card, with only the label to differentiate it from other SD cards. The label includes a silvery Kingston logo that probably serves as a kind of authentication mark.

Like all other SD cards, there is a physical write-protect switch on the left side of the 256 GB Kingston Class 10 UHS-I SDXC Card. Flick it down to prevent the card from being written to.

The 256 GB Kingston Class 10 UHS-I SDXC Card has an official formatted capacity of 256 GB. It comes pre-formatted in exFAT with a 256 KB cluster size.

Its actual formatted capacity is 256,422,969,344 bytes. This is slightly (422 MB) more than the official formatted capacity.

Testing The Kingston SDXC

The Testbed

Testing Methodology

We tested in Microsoft Windows 7 with the latest updates. We chose to use IO Meter 2008 as well as our own suite of test files. Here are the details of the two sets of test files we used :

• Large Files : 5 high-resolution videos (2,002,511,061 bytes)
• Small Files : 2,527 mix of low, medium and high-resolution photos (2,000,704,583 bytes)

To ensure that the much slower hard disk drive or solid state drive do not affect the results, we used a RAM disk to perform the copy and write tests.

All transfer rate tests were timed using a Seiko WC73-4000 stopwatch with a rated accuracy of 10 ms. A minimum of 3 test runs were performed, with additional test runs undertaken if the results were off by more than half a second. The closest group of 3 run times was averaged to obtain the final result.

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