Flash Speed FAQ

Should I buy the highest flash speed rating possible?

Flash memory cards are rated as multiples of 150KB/s (kilobytes per second) - so a 12x card has a data transfer (read/write) rate of 12 x 150KB/s = 1800 KB/s or 1.8MB/s. Card are generally available now as 40X, 60X, 80X, 133X, 150X and even higher in some cases.

A 60X card has a transfer rate of 9 MB/s etc...

If you consider the speed of the card itself and not the capabilities of the camera, phone or other reader then the higher the speed rating, the faster your memory card can store images.

Take 50 images of 2MBytes each = 100Mbytes of data, here is the estimated time it will take to transfer these images at the rated flash speed

• 10X will transfer at 1.2MB/s so it will take 83 seconds to transfer 100Mbytes of data
• 40x will take 16 seconds
• 80x will rake 8 seconds

However the flash card is only one of the parts responsible for transferring images. Your device must support this transfer rate. Putting high speed Z rated tires on your car will not really make it go any faster.

Usually only professionals who use expensive, specialized products can benefit from these high speed cards. Most people won't notice a difference because the actual performance of a flash card is limited more by your device than the flash card itself. Few people actually benefit from high-speed cards.

A camera has its own speed rating and when these products work together they'll work at the slowest common speed. If you use a 20X flash card in a camera designed to work at 10X speed, you'll be transferring data at the slower 10X speed.

Most camera manuals don't tell you what speed of flash card you should buy, usually recommending a type and maybe a manufacturer (who has often paid to be included in their recommended list). If your camera has resolution under five mega pixels, the speed rating of the flash card won't matter much. In fact many cameras will not work well with ultra high speed cards of 133X and 150X speeds because of the special formatting used to achieve these high speeds. The improvement you are likely to see in a higher rated card will be minimal and undetectable.

Should I buy high speed or not?

Professional photographers using professional-grade cameras should use high-speed flash (40X - 150X). If your camera has a pixel rate more than five mega pixels, you will benefit from a flash card with a higher speed rating. If your camera has a resolution less than five mega pixels, simply use cards rated less than 40X, this way you can ensure compatibility and not spend money unnecessarily on higher rated cards.

With image files quickly growing in size, the time it takes to store or write those files to a Flash card is becoming an important buying criterion for prosumers and professionals. Today, many Flash cards are sold with an "X" speed rating that is similar to how CD-ROM drives are sold. This rating system gives users a performance indicator of how fast the card can transfer images.

When comparing the X-speed ratings of Flash cards from different manufacturers, users need to beware that manufacturers define this rating differently and in some cases do not define it at all. Some definitions refer to the X-speed as "read" speed or "write" speed. Others use it to mean both and call it "data transfer" speed (referring to read and write speed). Kingston uses the "write" speed (found at www.kingston.com/flash) as the basis for its X-speed rating.

Definition of X Speed Performance
Flash cards with a higher X-speed rating are designed to perform faster. The X-speed rating can also be translated into another common measurement of performance - MegaBytes (MB) per second of write speed. To determine the actual MB per second, you must know the value of "X" and do the math using the multiplier number and the value of X as claimed by the product. For example:

1 KB = 1,000 Bytes; 1 MB = 1 million Bytes.

Kingston's Elite Pro/Ultimate Flash Cards "X" Speed Ratings
Kingston defines X-speed as the write speed, because users generally care more about how long it takes to write data to a Flash card when using it in a digital camera or cell phone. Typically, read speeds are higher than write speeds for Flash cards, so the write speed is more meaningful when measuring performance.

The table shows Kingston Elite Pro/Ultimate X-speed rating versus the comparable MB/sec as calculated from the write speeds.

Source: Kingston Engineering Labs in benchmark testing;
Write speeds are listed in the products' data sheets found at www.kingston.com/flash

As an example, Kingston's 2-GB CompactFlash Elite Pro card is rated at a 50X; this translates to a write speed of 50 * (150 KB/sec.) meaning 7,500KB/sec or 7.5 MB/sec.

To support these results, Kingston tested its Flash cards on high-end testers, such as those from Testmetrix®. These testers measure the true read and write speed of the Flash cards in a way that is less dependent on the multitude of host devices.

Is a Faster "X" Rating Always Better?
When a Flash card is rated at 50X, does this mean that data will transfer at 7.5 MB/sec. in any digital camera or other host device? Not necessarily.

A digital camera, cell phone, or other host device is itself limited by the speed of its interface to the Flash card. Often, the host device has a lower read and write speed than the Flash card, so the end result is that the Flash card cannot operate at its best performance level. A good example of this is that a digital camera may only support 10X write speeds, so using a 45X or faster Elite Pro card will not improve performance. Most cameras or other host devices do not have clearly documented Flash card interface read or write speeds, so it may be difficult to know your host device's exact capabilities.

As a general rule of thumb, digital cameras with up to 5 megapixels will work just fine with standard-speed Flash cards (less than 45X). Newer professional cameras designed for continuous shooting with specifications of greater than 5 megapixels will benefit the most from Elite Pro/Ultimate cards rated at 45X or above.

If using a high-quality Flash card reader to transfer data to a computer, a Flash card with a higher X-speed rating will generally transfer its data faster, thereby reducing the time to copy data from the Flash card to the computer's hard drive.

Kingston Elite Pro/Ultimate Flash Cards for Quality and High Performance
Kingston's Flash cards deliver on the quality and high performance needed by prosumers and professionals alike. These cards also have speed headroom to support users who plan to upgrade later to newer and faster host devices.

As the world's leading independent memory products manufacturer, Kingston uses only top-quality Flash chips and manufactures Flash products in state-of-the-art factories. All cards come with a lifetime warranty, 24/7 technical support and Kingston's legendary reliability, making Kingston the ideal memory choice for Flash storage devices.