The CompactFlash card speedway

How fast is your digital experience?

By Joe Farace

All CompactFlash cards are the same, right? All you need to do is buy whatever is cheap to capture your precious images. Wrong! Just as choosing the correct film for the assignment is important in traditional photography, choosing the right memory card is critical for digital capture. Here’s why:

They’re not all the same speed. Lexar was the first company to rate the speed of its flash memory cards and currently provides ratings for its Platinum and Professional lines. Most other memory card manufacturers also rate their products’ speed, but what does it really mean? The rating refers to the speed that data can be written to or read from a flash memory card.

Photographers often think their memory card’s speed and performance only make an impact when the card is in their camera, but speed impacts workflow when transferring data with a card reader, too. A “sustained speed-rating” is important because it allows the photographer to capitalize on the camera’s built-in functions, such as burst rate and video capture. When a card exhibits inconsistent high-speed performance, either function can be interrupted.

In media card specs and packaging, X represents the basic transfer rate of 150kb/second and increases are in multiples, signifying the card’s overall speed (e.g. 133X means 133 x 150kb/second =  about 19.48 MB/second). Historical Note: When people started storing data on CD-ROM discs, the same system was used. An embedded high-speed controller allows a flash memory card to perform at its best, but the bottom line is that the higher the X number, the faster the card.

The Big Three
200605bc_kingston Kingston may be better known for its computer memory than digital media, but offers a full slate of products including Ultimate 100X CompactFlash cards that are available in 1GB, 2GB, and 4GB capacities. These cards offer a 20MB/sec. read rate and a 16MB/sec. write rate, or 100X. Kingston defines its X-speed by the write speed because read speeds for memory cards are higher than write speeds and they believe photographers “care more about how long it takes to write data to a digital camera” than read it. I think we care about both speeds because either way, time is money. The Ultimate 100X cards carry a lifetime guarantee. A Kingston representative told me, “If it’s broke, we will fix it or replace it.”

200605bc_lexar Lexar 133X Professional CompactFlash memory cards have a 20MB/sec minimum sustained read and write capability and are available in 1GB, 2GB and 4GB capacities. The cards are bundled with Image Rescue 2.0 software and a 30-day trial version of the Photo Mechanic 4.3 image browser. Image Rescue can recover lost or deleted JPEG, TIFF and RAW files even if you’ve erased them, reformatted the card, or if the memory card has been corrupted. Lexar’s Pro cards are backed by a lifetime limited customer-satisfaction warranty. (See “When Good Cards Go Bad”)
As I was finishing this story, Micron Technology, one of the leading semiconductor providers, announced they’ve entered into an agreement to acquire Lexar.

200605bc_sandisk Although not specifically speed rated, SanDisk Extreme III memory cards feature ESP (Enhanced Super-Parallel Processing) for high performance producing 20MB per second sequential read and write speeds. CF cards are available in 1GB, 2GB, 4GB, and 8GB capacities. Every SanDisk Extreme III CompactFlash card comes with RescuePRO recovery software that lets you preview recoverable data before you try to retrieve it. SanDisk memory cards have a lifetime-limited warranty.

Real World Testing
To see how fast these three cards performed under real world conditions, the crack Farace Testing Labs staff designed a test to see how fast the cards really are. Like Consumers Reports, the cards used for the test were not requested from the manufacturers specifically for this article so there was no chance any ringers were sent. Cards tested included a 2GB Kingston Ultimate, a 2GB Lexar Professional, and a 1GB SanDisk Extreme III. Write-speed tests were conducted using a Canon EOS 30D set to simultaneously capture a RAW file plus Large JPEG, giving the camera the largest possible amount of data to write. Write times were measured by timing the camera's data transfer indicator light using a TAG Heuer stopwatch.

Lexar and SanDisk tied for first place at two seconds each; the Kingston took three seconds. JPEG-only capture on all three cards was virtually instantaneous. I leave it to you to decide if that difference is significant to your camera and type of photography.

Big Three Card Readers
While there are those, especially in the camera industry, who think photographers will connect their camera directly to the computers using the USB cords they thoughtfully provided, the reality is that the media and camera are often in different places at the same time. Hence the need for a card reader. All of the big three offer card readers with some similarities and some differences. I tried three different ones for this story.

200605bc_kingstonreader The Kingston USB 2.0 Hi-Speed 15-in-1 Reader sells for less than $25 and supports Compact Flash Type I/II, SD, SD High Speed, miniSD, MMC, MMCplus, MMCmobile, MMCmicro (adapter Required), RS-MMC, microSD (adapter required), Memory Stick, Memory Stick Pro, Memory Stick Pro Duo, SmartMedia, and Microdrive. It comes with a 5-year warranty and free customer support.

200605bc_lexarreader Lexar offers separate Lexar Professional CompactFlash Readers in both USB 2.0 and FireWire connections. The CompactFlash Readers are stackable and designed to connect multiple readers with a single connection. Up to four FireWire readers can be daisy-chained and up to four USB 2.0 CompactFlash Readers can be connected via Lexar’s Professional 4-Port Hub for simultaneous image file transfers. The readers support Lexar’s ActiveMemory and LockTight technologies. With AMS, camera settings (in supported cameras) can be saved to the card to prevent having to reenter these settings each time. LockTight prevents unauthorized people from accessing your image files. Both models sell for a little over $60 each, but stacking them and making simultaneous data transfers can save time for event photographers who need to get image files into the computer and printed in a hurry.

200605bc_sandiskreader_1 SanDisk’s ImageMate 12-in-1 is a multi-card USB 2.0 reader that, like all USB 2.0 devices, is backwardly compatible with the slower USB 1.1 ports. The ImageMate 12-in-1 has the ability to write data to and read data from CompactFlash Type I/II, SD, miniSD, MMC, RS-MMC, Memory Stick including PRO, Duo and PRO Duo, along with SmartMedia and xD cards. The $35 card reader can be used without or with a bundled and removable cradle that keeps it from getting lost on the desktop but might be extra baggage on the road.

Real World Testing
USB 2.0 has a raw data transfer rate at 480MB/second and it is rated at 40 times faster than its predecessor, the once ubiquitous USB 1.1. FireWire is rated at 400MB/sec., but there are differences in the way the systems are designed. Built from the ground up for speed, FireWire uses peer-to-peer architecture and intelligent peripherals can negotiate bus conflicts to determine which device can best control data transfer. USB 2.0 uses the more traditional “Master-Slave” architecture in which the computer handles arbitration functions (that’s why it costs less) for managing data flow to, from, and between peripherals. Some people claim that this difference makes FireWire faster but my real world tests bore out the raw MB/sec. numbers. Using a 2GB Kingston CF card with a mix of 83 RAW and JPEG images, the USB card readers transferred them to my hard drive in 26 seconds; the reader connected via FireWire took 44 seconds. In all the testing done for this story, I attempted to reproduce what you could expect in real world usage. “Your mileage,” as the EPA says, “can vary.”

Comments (2)

This information comes at a great time. I'm in the process of ordering cf cards and didn't know what to choose. I'm now enlightened and can make a wise decision.
Thanks

Joe Farace is always a good read and if you E-mail him he'll actually get back to you. The article on compact flash cards was quite informative. As much as I read all sorts of articles this is the first one that actually explains CF speed in an understandable manner. As usual great testing, Joe.

Peter Silowan
Braintree, MA

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This page contains a single entry from the blog posted on May 1, 2006 12:02 AM.

The previous post in this blog was When good cards go bad, a personal testimonial.

The next post in this blog is Soft proofing in Adobe Photoshop.

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