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SanDisk ships 'X4' flash chips

SanDisk X4 flash memory chips allow consumers to store more data on tiny Secure Digital flash cards.

SanDisk said Monday that it is shipping memory chips that will allow consumers to store more data on tiny Secure Digital flash cards.

SanDisk X4 chip
SanDisk X4 chip SanDisk

The Milpitas, Calif., company's X4 technology packs four bits of data into each memory cell. To date, flash memory chipmakers typically stored one bit or two bits per cell. Each individual die--or chip--holds 64 gigabits of data, or 8 gigabytes. This is the highest capacity per die in the industry, according to SanDisk.

The technology is not yet shipping in cutting-edge retail products, however: it is currently being used in 8GB and 16GB SDHC (Secure Digital High Capacity) cards as well as 8GB and 16GB Memory Stick PRO Duo cards, the company said.

Future related technology from SanDisk--possibly not based on current X4--is expected to yield SD flash cards that hold 64GB of data and larger capacities. Currently, mainstream SanDisk SD cards top out at 32GB.

Flash memory cards sold at retailers are typically not as reliable as solid-state drives--which also use flash chips--sold with laptops. And the higher the density per chip and the more bits per cell, the bigger the challenge for maintaining data reliability. SanDisk says it has met this challenge.

"Our challenge with X4 technology was to not only deliver the lower costs inherent to 4-bits-per-cell but to do so while meeting the reliability and performance requirements of industry standard cards," Sanjay Mehrotra, SanDisk's president and chief operating officer, said in a statement.

But X4 will, for the time being, be hampered by poorer performance and endurance than X3 (3-bits-per-cell) technology, said Gregory Wong, founder and principal analyst at Forward Insights, which does research on flash memory technology.

The memory technology itself--the 4 bits per cell 64-gigabit memory--is codeveloped and co-owned by SanDisk and Toshiba. The X4 controller technology is solely owned by SanDisk.