SD Memory Cards for Professionals
(Ed.: For more memory card performance data, including SDHC and Compact Flash cards, please check out our most updated charts. You can find the SDHC charts here and the Compact Flash charts right here.)
The prices of portable memory cards have decreased to almost ridiculous levels: 8 GB SDHC cards now start at only $12. However, enthusiasts don’t want just any memory card—they want one that delivers high write throughput for their devices such as digital cameras, and fast reads, so they can copy contents to their systems quickly. These elite products are much more expensive, so we invited eight popular brands to a shootout.
SD Card Details
The Secure Digital (SD) card was invented by SanDisk in 2001 and was based on the multi-media card (MMC) standard. Technically, SD is similar to MMC, but adds digital rights management based on CPRM. SD cards also feature a write protection switch, but it is not a hardware feature: the client device has to handle both settings appropriately.
The 2 GB capacity defined by the SD 1.1 standard wasn’t enough as card sizes grew, so the SD 2.0 or SDHC standard was added. It allows for capacities of up to 32 GB today; the standard is potentially ready for capacities of up to 2 TB. SDXC will follow next year, as 32 GB may remain the limit for the SDHC standard. Note that SDHC and SD cards are identical from the outside, so be sure your device supports SDHC before purchasing such a card (4 GB and up).
Classes 2, 4, 6
The first SD cards could be read at 3.6 MB/s and written at 0.8 MB/s. Faster cards were required by the increasing resolutions of digital cameras, as well as more demanding consumers. As a result, SDHC was divided into three classes: 2, 4 and 6; the numbers represent the minimum sustainable write throughput in MB/s.
It’s not only high resolution digital SLR cameras that require fast memory cards, allowing them to write several photos per second onto the storage device. Another key application is multi-purpose, high-speed mobile storage, or using these cards as system drives via USB or eSATA card readers.
We asked Kingston, Lexar, OCZ, Patriot, PNY, Sandisk, Silicon Power and Transcend to send us their fastest and highest capacity SD cards for review. Let’s look at the 13 cards between 4 GB and 32 GB that we received.