Tuesday, January 03, 2017

What NVMe SSD's are & Why they are Worth the Expense

Solid state drives (SSD's) are able to perform functions faster than traditional hard disk drives (HDD's) because of the differences between their physical makeup. Traditional hard drives rely upon magnetic on-and-off switches and a reader called a head, (much like what an old record player looks like), to read from the disk. When a certain area of the disk needs to be read, the heads move to that section of the disk. The head continues moving to various non-sequential sectors of the disk until all of the requested data is gathered into RAM where it is then served up to the user.

SSD's utilize flash memory chips allowing faster and more direct access. SSD's also have more predictable and consistent wear across the chips as data is saved using an algorithm designed specifically so that wear to the chips occurs at an even rate. NVMe, or Non-Volatile Memory Express is a technology used in the newest type of SSD.

NVMe SSD's Defined & Why they are Worth the Expense

Prior to NVMe, SSD's connected to a device's motherboard using SATA or SAS connections. SATA is the most common connection type, but was originally designed to connect with hard disk drives. This means SATA is not as advanced as the solid state drives themselves, and like anything with computers, the slowest moving part is as fast as your device can function.

What is NVMe?

NVMe is a logical device interface designed specifically for use with SSD's. As a result, NVMe is better prepared to handle the faster response times in addition to the multiple streams of data that SSD's can process, unlike their serial HDD counterparts. In other words, traditional hard drives process singularly while solid state drives can process paralleled or multiple streams at once, much like the difference between a single CPU versus a dual or quad-core CPU.

How does NVMe work?

Part of the process for both HDD's and SSD's connected via SAS and SATA is that they require translation of the data from parallel to serial and back to parallel streams. This is because SAS and SATA interfaces exist on controllers only capable of serial or singular communications, regardless of the drive capability. NVMe, which is only compatible with solid state drives, is able to transmit parallel streams of data to and from the drive. As a result, NVMe removes the need for an on-board controller and the extra translation the controller requires by extending the parallel PCIe bus directly to the SSD. Removing the controller removes inherent latency making NVMe SSD's even faster than SSD's using SAS or SATA interfaces.

In the image below created by Intel, you can clearly see the differences in response times of the different types of drives and their corresponding connector types.

As with anything tech, newer technologies usually cost more but often become the norm over time. If you are purchasing a new device and efficiency or response times are an important factor in your purchase, you should seriously consider an SSD using NVMe. With all other factors the same, an SSD using an NVMe connector is going to be much more responsive than an SSD using a SAS or SATA connection as a result of removing the controller latency associated with SAS and SATA.

As always, technology continues to change, new acronyms become everyday language and keeping up is not only important, it is vital in knowing where to spend your hard earned dollars!

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