The SSD with its NAND-based flash memory has been the hip, silent, power-efficient, and fast data storage device of late. And now it's too fast. Well, no not really. Basically the technology is certain to become too fast for the existing SATA interface, which is the most common portable system interface today for connecting thin laptops, Ultrabook™ devices, and tablets to an SSD.
The official SATA 3.0 interface specifications support a native transfer rate of 6.0 Gb/sec - a maximum transfer rate of 600 MB/sec. The SATA data transfer rate performance has been good over the past four years since the SATA-IO group released the standards in 2009. However, current mobile SSD SATA performance like Toshiba's newly announced HG6 series is now approaching the SATA interface performance limit with the HG6 60GB to 512GB1 capacity models reaching sequential read operations at 534 MB/sec2 (max.) and sequential write at 482 MB/sec (max.).
The M.2 form factor SSD with support for PCI Express (PCIe) is considered to be the industry's next generation of solid state storage technology, moving us beyond 6Gb/sec SATA. M.2 is designed specifically as an internally mounted computer expansion card to replace the mSATA connector found in many applications requiring a small form factor SSD. Actually, the M.2 standard is an implementation of the SATA Express computer bus interface and SATA 3.2 standards, which provides support for SATA 3.0 and PCIe 3.0, and that is where the hardware interface performance gets exciting again.
While the M.2 form factor's physical dimensions will enable more storage capacity than the mSATA module with its longer length options and ability to populate memory components on both sides of the card, an M.2 SSD with a PCIe capable controller on board will relieve the bottleneck that is SATA 6 Gb/sec, and allow impressive performance. We'll all likely be talking in GB/sec performance then. For now, Toshiba is now offering the HG6 series SSD in an M.2 form factor option and a SATA-capable controller. But inevitably, the mobile computing market, in its continuous attempt to provide consumers with the ultimate computing experience, will be moving to the advanced, high speed PCIe bus interface, which is capable of multiple shared address/data lines and at least double the data transfer rates of SATA.
As usual, I expect to see the cost versus necessary performance arguments going forward with PCIe enabled SSD technology within the mobile computing space. Nevertheless, end users will continue to appreciate the future speeds of system access, load times, and system responsiveness, which will make their older system feel like an inexpensive electronic calculator.
Ultrabook is a trademark of Intel Corporation in the U.S. and/or other countries.
1Definition of capacity: Toshiba defines a megabyte (MB) as 1,000,000 bytes, a gigabyte (GB) as 1,000,000,000 bytes and a terabyte (TB) as 1,000,000,000,000 bytes. A computer operating system, however, reports storage capacity using powers of 2 for the definition of 1GB = 230 = 1,073,741,824 bytes and therefore shows less storage capacity. Available storage capacity (including examples of various media files) will vary based on file size, formatting, settings, software and operating system, such as Microsoft Operating System and/or pre-installed software applications, or media content. Actual formatted capacity may vary.
2Read and write speed may vary depending on the host device, read and write conditions, and file size.