Along with Toshiba, SanDisk at the International Solid-State Circuits Conference today announced plans to ship an ultra-dense form of NAND flash memory that promises a breakthrough in storage. Called X4, the technology uses a special memory controller that maintains data traffic speed while still fitting four bits of data per cell. The approach lets SanDisk and Toshiba place 8GB of memory on a single chip, twice as much as before, and while still maintaining a transfer speed of 7.8MB per second.

As four of these chips are often stacked together in a single package, the technology potentially doubles the amount of storage available on a high-end flash memory die to 64GB but should remain small thanks to SanDisk's more recent 43 nanometer manufacturing process. Toshiba only just started making 32GB packages this past fall.

The first X4-based products should arrive during the first half of this year, with memory cards being the most immediately recognizable offerings; no mention has been made of third-party products containing the larger-capacity flash, though Toshiba has regularly supplied Apple with memory for the iPhone and iPod touch as well as other competing device makers.