Samsung unveiled its new XS175 line of SSDs today, with capacities of up to 1.6TB and a brand-new storage interface. The new drive uses the Non-Volatile Memory Express (NVMe) standard, which is meant to boost SSD performance by transitioning to using PCI Express for transfers rather than conventional SATA.
The Serial ATA standard has been extended multiple times since it first debuted in 2003, but it was fundamentally designed for spinning disks. Many of the features that the SATA/AHCI interface enables, like NCQ (Native Command Queuing) were designed to address problems with that type of media — not for modern SSD architectures. (See: Crucial M500: The first 1TB SSD, priced at just $0.60/gig.)
Normally, enterprise products aren’t of much interest to the consumer market, but NVMe is a feature that’s headed for the consumer space before too long. The performance benefits over AHCI are significant — NVMe is designed to allow a drive to create multiple queues, using a model that more closely maps to the multiple NAND channels in an SSD rather than relying on spinning media to access data sequentially. It supports up to 64K submission and completion queues, with each queue holding up to 64K of entries. Queues can be prioritized or weighted differently to speed system accesses.
Samsung is the first company to implement NVMe, and it claims the standard will offer significant performance advantages. While plenty of other SSDs have used the PCIe bus before now, the benefit of NVMe is that it’s a standardized interface that won’t require specific manufacturer drivers in the future. Once widely adopted, you’ll need just a standard driver that can easily be bundled with the operating system.
Those of you who follow the storage market may be aware that the next generation of SATA controllers, dubbed SATA Express, are adopting PCI Express as their interface. SATA Express and NVMe are complementary, not competing technologies. Specifically, SATA Express specifies the design of the physical connectors and hardware, while NVMe provides the driver and interface. According to the consortium that’s in charge of SATA Express, the decision to move to NVMe was made because it offers increased performance and significantly improved power management without requiring a full doubling of bandwidth.
The current SATA transfer rate tops out at 6Gbps, while SATA Express bumps this to 8Gbps. That might not sound like much, but the SATA-IO working group believes that the benefits of NVMe, combined with the modest bump in raw bandwidth, will deliver a satisfying performance kick.
The first SATA Express chipsets are expected in 2014, with Intel’s Broadwell. SATA Express is backwards compatible with AHCI as well as supporting NVMe — there’s no reason to worry about drives becoming incompatible due to the shift.
0 comments:
Post a Comment