USB Flash Drives & Digital Flash Memory
USB Flash Drives & Digital Flash Memory Categories
|Approximate number of images per card capacity
|Approximate number of video minutes
|Approximate number of songs (4 minutes song)
|Approximate number of Emails
|no attached files
Common information -content from Wikipedia (http://en.wikipedia.org/wiki/Comparison_of_memory_cards)
||Thinner (3.3 mm), flash based only, sizes available up to 512MB
||Thicker (5.0 mm), older flash based, but usually Microdrives, sizes available up to 128 GB
||Very thin (45.0 × 37.0 × 0.76 mm thick), no wear levelling controller, sizes available up to 128 MB
||Siemens AG, SanDisk
||Thin and small (24 mm × 32 mm × 1.4 mm), sizes available up to 4 GB
||Compact size (24 mm × 18 mm × 1.4 mm), sizes available up to 2 GB
||Compact size (24 mm × 32 mm × 1.4 mm), faster, optional DRM, sizes available up to 2 GB
||Sub compact size (14 mm × 12 mm × 1.1 mm), optional DRM, 16MB - 1GB
||Panasonic, SanDisk, Toshiba, Kodak
||Small (32 mm × 24 mm × 2.1 mm), DRM, sizes available up to 2 GB
||Compact size (21.5 mm x 20 mm x 1.4 mm), DRM, available up to 2 GB
||Sub compact size (11 mm x 15 mm x 1 mm), DRM, available up to 4 GB
||Physically the same as SD, but offers higher capacity and transfer speed, available up to 64 GB
||Physically the same as miniSD, but offers higher capacity and transfer speed, available up to 32 GB
||Physically the same as microSD, but offers higher capacity and transfer speed, available up to 32 GB
||Thin and narrow (50 mm x 21.5 mm x 2.8 mm), optional DRM, available up to 128 MB
(not to scale)
|Thin and narrow (50 mm x 21.5 mm x 2.8 mm), faster, optional DRM, Memory up to 4 GB
||Compact size (31 mm x 20 mm x 1.6 mm), optional DRM, Memory up to 128 MB
||Compact size (31 mm x 20 mm x 1.6 mm), optional DRM, available up to 32 GB
||Compact size (31 mm x 20 mm x 1.6 mm), faster , optional DRM, available up to 32 GB
||Sub compact size (15 mm x 12.5 mm x 1.2 mm), optional DRM, available up to 16 GB
||Thin and small (20 mm × 25 mm × 1.78 mm), electrically identical to SmartMedia, no wear levelling controller, available up to 512 MB
||Thin and small (20 mm × 25 mm × 1.78 mm) but slower read/write, no wear levelling controller, available up to 2 GB
||Thin and small (20 mm × 25 mm × 1.78 mm) and faster than previous two versions, no wear levelling controller, available up to 2 GB
|USB flash drive
(not to scale)
|Universally compatible across all computer platforms, but larger size suits them better to file transfer/storage instead of use in portable devices, available up to 256 GB
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
- 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
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.
Flash Memory Cards and X-Speed Ratings
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:
| Value of X = 150 KiloBytes*
per second, noted as 150 KB/sec.
| 50X = 50(multiplier of 150KB/sec) =7,500 KB/sec
= 7.5 MB/sec
1 KB = 1,000 Bytes; 1 MB = 1 million
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.
| Kingston's Elite Pro/Ultimate Flash Cards
| Elite Pro/Ultimate X Speed
|| Comparable MB/sec.
Source: Kingston Engineering Labs in benchmark
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
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
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
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.
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