Silicon Power Memory Cards |
Secure Digital Memory Cards by Silicon Power meet the single
burst and sequential shooting needs of Intermediate/Professional photographers.
These memory cards can be used in a variety of digital products: digital music
players, cellular phones, handheld PCs (HPCs), digital cameras, digital video
camcorders, smart phones, car navigation systems and electronic books.
Shop for Silicon Power Memory at these stores
||Compact Flash® Card Size
||Silicon Power 128GB 400x Cf card
||Silicon Power 200x High Speed Compact Flash CF Memory Cards SP008GBCFC200V10: $35.75
||Silicon Power CF 4GB 133x: $21.50
||SD Flash Card Size (SDHC)
Please verify that your device such as cellular phone or digital camera
supports SDHC cards. SDHC cards are not compatible with standard SD host devices and card readers, and will only work on SDHC
||Silicon Power SDHC 16GB Class 6: $52.50
||Silicon Power 8GB SDHC Class-6 High Capacity SD Memory Card: $29.20
||Silicon Power 4GB SDHC High Capacity SD Memory Card: $15.95
||Silicon Power Secure Data (SD) 1GB 80X: $6.85
IDE (ATA) emulation speed is usually specified in "x" ratings, e.g. 8x, 20x, 133x. This is the same system used for CD-ROMs and indicates the maximum transfer rate in the form of multiplier of the data rate of an audio CD, which is 150 KB/s.
where R = transfer rate, K = speed rating. For example, 20x rating means 20 * 150 KB/s = 3,000 KB/s = 3 MB/s.
These are manufacturer speed ratings and actual transfer speed may be higher or sometimes lower that one shown on a card
There are different speeds of SD card available. The official unit of measurement is the Speed Class Rating; an older unit of measurement is the × rating.
Speed Class Rating
The Speed Class Rating is the official unit of speed measurement for SD Cards, defined by the SD Association. It is equal to 8 Mbit/s, and it measures the minimum write speeds based on "the best fragmented state where no memory unit is occupied
The following are the ratings of some currently available cards:
Even though the class ratings are defined by a governing body, like × speed ratings, class speed ratings are quoted by the manufacturers but unverified by any independent evaluation process.
- Class 2: 16 Mbit/s (2 MB/s)
- Class 4: 32 Mbit/s (4 MB/s)
- Class 6: 48 Mbit/s (6 MB/s)
- Class 10: 80 Mbit/s (10 MB/s)
Important differences between the Speed Class and the traditional CD-ROM drive speed measurement ("×" speed ratings) are:
On 21 May 2009, Panasonic announced new class 10 SDHC cards, claiming that this new class is "part of SD Card Specification Ver.3.0". Toshiba also announced cards based on the new 3.0 spec As of December 2009, the SD Association's Web site does not include information on this new class or new specification.
- 1. the ability of the host device to query the SD card for the speed class and determine the best location to store data that meets the performance required
- 2. class speed defines the minimum transfer speed.
Since the class rating is readable by devices, they can issue a warning to the user if the inserted card's reported rating falls below the application's minimum requirement.
The × rating is a unit of measurement equal to 1.2 Mbit/s. It is derived from the standard CD-ROM drive speed of 1.2 Mbit/s. Basic cards transfer data up to six times (6×) the data rate of the standard CD-ROM speed (7.2 Mbit/s vs 1.2 Mbit/s). The 2.0 specification defines speeds up to 200×, but unlike the class rating system, does not mandate that x-ratings measure the card's sustained write-speed. For most cards, the maximum read speed is typical faster than its maximum write speed, leading some manufacturers to use read-speed as the ×-rating measurement. Other vendors, such as (Kingston, use write-speed.[
This table lists common ratings and minimum transfer rates.