FAQ

When CompactFlash was first designed, devices and applications didn't really exceed the read-write speeds of the first generation cards. This changed as digital camera resolutions grew, and uses of CompactFlash in embedded systems and other speed dependent devices became common. There are two main factors in how fast a CF card can write and read data. The first is the flash memory cells themselves. The second is the IDE controller chip on the card, which coordinates reads, writes, erasure, error correction, etc. As flash memory and more importantly controllers have gotten faster, CF cards perform much better. Vendors like Lexar Media, Inc. began using a the same speed rating that CD-RW manufacturers use to designate the speed of CD Burners with 1X being a write speed of 150KB/sec. The following is a table of common CompactFlash card write speeds.

When used with devices that have high throughput requirements like high resolution digital cameras, the high speed cards make a significant difference. Typically read speeds are even faster than the rated write speeds. Unless a very high performance factor is necessary, 45X cards currently provide the best performance to price ratio.