SD cards are commonly used to expand the memory of digital cameras, camcorders, voice recorders and cell phones. Once the files are saved to the SD card, you can insert the SD card into your computer's SD reader to view and save the files. Like hard drives and other computer components, not all SD cards are created equal, with the most noticeable difference being the speed at which the data is written to and read from the card. As card sizes increase, the speed of the SD card begins to become more important. HD Tune and Crystal Disk Mark are two programs that allow you to test the transfer rate of your SD cards.
Download the Crystal Disk Mark software (see Resources). Once the file is downloaded, double-click the file to launch the installer, then follow the onscreen prompts to complete the installation.
Insert the SD card into your SD reader, then open the Crystal Disk Mark software.
Select your SD card from the drop-down menu on the top right of the Crystal Disk Mark software window.
Click "All" on the top left of the software to begin the test. After the test is run, the numbers shown will indicate, in megabytes per second, how long it took to write and read files of varying file sizes displayed beside the data.
Visit the HD Tune download page and download HD Tune (see Resources). Save the file in an easy-to-find location, such as your desktop.
Double-click the downloaded file to launch the installer. Follow the onscreen prompts to complete the installation process.
Insert the SD card into your computer's SD card reader.
Open the HD Tune software, then select your SD card from the drop-down menu in the top left of the software window.
Click either the "Read" or "Write" radio button below the "Start" button to test the read or write speed and place a checkmark in the box labelled "Transfer Rate." If you would like to test both read and write speeds, run the test twice--once with "Read" selected and once with "Write" selected.
Click "Start" to begin the test. Once the test is complete, the speed will be displayed beneath the section labelled "Transfer Rate" on the right side of the tab labelled "Benchmark."