A massive decline in the price of NAND flash memory, the chips that store photos in digital cameras and music in iPods, is prompting innovation among companies trying to increase sales.

A few of the items users are likely to see more widespread in gadgets this year include greatly expanded storage capacity in SD (secure digital) cards, USB flash sticks, and internal storage, as well as new, lower-cost SSDs (solid-state disks) in notebook computers.

The price of mainstream 4Gb SLC (single-level cell) NAND flash memory chips has fallen 73 percent since mid-August to $4.96 late Thursday, according to DRAMeXchange Technology, which runs an online clearinghouse for the chips. The chips hit a high of $18.50 on Aug. 14. The price of 4Gb MLC (multi-level cell) NAND flash chips have taken a slightly worse dive, 75 percent down to $2.23 on Thursday, compared to its summer high of $8.85 per chip.

The difference between SLC and MLC is cost and life span. SLC normally costs about three times more than MLC, and has a lifetime of 100,000 write cycles. MLC has a lifetime of only 10,000 write cycles.

Toshiba and Samsung have both developed new 128GB SSDs based in MLC NAND to expand their use in notebook PCs. The new SSDs are less expensive, giving notebook PC designers more choices in storage.

"At 128GB, you're giving consumers the kind of storage space they expect in a notebook," said Jim Elliott, director of flash marketing at Samsung, in an interview.

To work around the lifespan issue, Toshiba and Samsung use controller chips to spread writes across the drive to avoid wearing out any one portion too quickly.

The new MLC-based drives are an important step forward for SSDs in the battle against hard disk drives (HDD). At 128GB, an SSD stands a far better chance of replacing an HDD in laptop computers because it removes some of the high-capacity advantage HDDs hold.

SSDs have several advantages over HDDs; they're lighter, more rugged, consume less power, make no noise, and enable a computer to start up and load software faster than HDDs. But SSDs are a lot more expensive than HDDs, which is why they're mainly used in the business laptop market, where users are willing to pay more for performance and reliability.

Elliott believes SSDs for PCs will account for 27 percent of NAND consumption by 2011, particularly in business laptops and mobile devices.

SanDisk has taken a slightly different route in SSDs than Toshiba and Samsung. The company made a 72GB SSD in a thinner form factor aimed at mobile devices. The drive takes up less space, so it could be used in a range of mobile devices, said Iri Trashanski, director of strategic business development at SanDisk.

He doesn't believe there will be a market for 128GB SSDs for a while.