Mainstream flash making eyes at 3Xnm tech

The NAND foundries and SSD suppliers are moving to sub-40nm process technology in its pursuit of higher capacity and lower cost. Toshiba and OCZ are both revving their product range to offer better flash to customers.

Micron and Intel, like Toshiba, have already introduced sub-40nm product. The smaller the process technology the larger the number of flash cells that can be fitted onto a wafer and this lowers the cost per cell.

The other technique for cost reduction and capacity increase is to increase the number of bits per cell, with 2 and 3-bit multi-level NAND cells here already and 4-bit coming - SanDisk is already shipping some of the stuff. However, MLC NAND is slower than single level cell (SLC) NAND and has a shorter life in terms of write cycles, making process technology shrinkage a more certain way to boost capacity and lower cost.

Toshiba, number two by revenue in the industry, is adding more 32nm flash products as it moves from its mainstream 43nm process to 32nm. It is going to introduce a SG2 product with 128MB capacity and a mini-SATA interface and a format smaller than either a 2.5-inch or 1.8-inch hard disk drive.

Toshiba says that the product is one-seventh the volume and one-eighth the weight of 2.5-inch form factor SSDs, and consumes a fraction of the power. The highest SG2 sequential read speed is 180MB/sec with the equivalent write number less than half that at 70MB/sec. These products are intended for netbook and similar portable devices.

The HG3 products are faster and larger with a 250MB/sec sequential read speed and 180MB.sec sequential write speed - obviously Tosh could make its SG2 write faster if it wished. It will offer the HG3 in 1.8-inch format at capacities of 64GB, 128GB and 256GB. A 2.5-inch variant will have a 512GB capacity point as well.

The SG2 and HG3 products will be compatible with the Windows TRIM command said to increase their efficiency. According to Toshiba, with earlier SSDs a data block from which data was deleted was flagged as not in use and ignored by the controller. Once all the memory cells in the SSD were written to once, this approach slowed down operation.

TRIM enables Windows to tell the SSD controller that the data can be deleted, freeing the blocks for subsequent use and maintaining SSD performance across its life.

OCZ

Toshiba offers complete SSDs using its own controllers and its own chips. OCZ offers SSDs using bought-in chips from IMTF, Samsung and Toshiba and controllers from various sources. It is also moving to a 3X process technology for its chips, 34nm from IMTF and 32nm from Samsung and Toshiba.

The 2.5-inch Vertex line is for the enterprise, enthusiast and mainstream markets and it will move to 3Xnm chips with a mix of SandForce and Indilinx controllers in the Vertex 2 set of products. With SandForce controllers read speed of 270MB/sec and write speeds of 260MB/sec are mentioned, using SLC flash. MLC product will also be available.

A 512GB Vertex 2 product will come in the second quarter along with the other 3Xnm Vertex product.

OCZ has an Agility brand for the mainstream value market, and that will get a 512GB model in the second quarter as well. Also for the mainstream market there will be a Solid 2 brand SATA SSD with TRIM support and MLC flash. It's aiming to offer a $99 32GB MLC SSD in February for this market, using an Indilinx Amigos controller. The branding for this has not been decided, but the $99 price point looks terrific.

There is a high capacity, high performance Z-Drive line, using Indilinx/LSI controllers and an internal RAID 0 configuration. It is expected that OCZ will introduce 512GB and 1TB capacity points for enterprise customers with significantly high speed operation: 1400MB/sec read and 1500MB/sec write.

There are other Z-Drive products with lower speeds down to 350MB/sec read and 225MB/sec write which will be less expensive.

The sub-40nm Z-Drive products will be available this quarter.

OCZ' 3.5-inch form factor MLC Colosuss line will move to sub-4Xnm technology in the second quarter. A third generation 3.5-inch SSD line using SandForce controllers is in a research and development phase at OCZ and any product is not expected until after the third quarter of this year and maybe not until 2011.

Samples of the new Toshiba drives will be available in the first quarter of this year, with general availability in the second quarter.

The industry is not stopping at 3Xnm process technology; Intel and Micron have plans to move to a sub-3Xnm generation of process technology to get even higher capacities and lower costs. For all this continuing improvement in SSD capacity and cost no one knows when flash will be both cheap and reliable enough to prompt a mass changeover from hard drives.

Everyone thinks customers will pay a premium for flash speed compared to hard drives but the additional cost customers are willing to pay at any capacity point, such as 128GB or 256GB, over an equivalent capacity hard drive is just not understood. It's a case of wait and see, shipping higher capacity and cheaper flash product as technology advances permit. ®