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How We Tested

Before actual testing was conducted, the cards were separated by type, (SD and CF) and then “prepared” for testing. By prepare we mean that each was wiped using a technique that conforms to the United States Department of Defence 5220.22-M specification for wiping storage.

In brief, this technique writes over all the storage locations on the memory card three times – first with a fixed value (0x00), then it’s compliment value (0xff) and finally with some random values. The card is then verified to ensure that all previous data and memory patterns are permanently erased.

The cards were then formatted. For the 2GB SD cards, this was performed with a Canon EOS-1D Mark II (FAT16). The 4GB CF cards were FAT32 formatted on a Windows XP Professional PC.

We used two card readers for the read and write tests for Protocol 1 (1.01GB consisting of 4,139 mixed files in 697 folders): a Crucial 8-in-1 USB2.0 (model number: CR-T1-U28) and a SanDisk ImageMate 8-in-1 USB2.0 (model number: SDDR-88). A “big-up” to both companies for kindly supplying these.

After initial testing with Protocol 1, it was deemed that the SanDisk card reader was the quicker multi-slot reader in all tests and was therefore used for Protocol 2 (1.01GB consisting o 203 JPEG images in one folder). We also decided to use this protocol with the Lexar USB2.0 single slot reader that came bundled with the Lexar SD card.

The test files were copied to and from each card. The stopwatch was started upon clicking the paste option and then stopped when the copying progress window disappeared. MB/sec was then calculated on the basis that

For the camera write tests, a Canon EOS-1D Mark II was used. The total MB of the images captured was summed and divided by the time recorded, (MB/s).

''A breakdown of all the protocols and tests can be found at the end of this grouptest'

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