SanDisk this week introduced its SanDisk Extreme IV line of CompactFlash digital media cards - which it calls the “world’s fastest” - as well as debuted new high-capacity 4GB SD digital media. The Extreme IV cards, designed for professional photographers who require high-performance for medium format and high-end digital single lens reflex (SLR) cameras, are available in capacities of up to 8GB; they deliver minimum read and write speeds of 40MB/sec, which the company claims are the fastest flash memory cards in the world. SanDisk also introduced its new SanDisk Extreme FireWire reader that can transfer images from the SanDisk Extreme IV cards to a computer at up to 40MB/sec. The cards are available in 2GB, 4GB and 8GB capacities for $160, $320, and $640.