Advantages and Disadvantages of SSHDs (Solid State Hybrid Drives)

Is this cross between a hard drive and an SSD right for you?

Solid-state hybrid drives blend conventional platter-based hard drives and the new solid-state drive technologies. If you have been looking at upgrading your hard drive for a laptop or desktop computer, you may have come across the term SSHD. This is a new marketing term coined by Seagate to label what had previously been referred to as hybrid hard drives.

SSHDs work on any computer regardless of the operating system, providing an appropriate bay or connector is available.

Seagate 1TB SSHD Hard Drive

Benefits of the SSHD

The tagline from Seagate for their SSHD lineup is "SSD Performance. HDD Capacity. Affordable Price." This marketing slogan is an attempt to communicate that these new drives offer the benefits of the two technologies without any significant cost increases.

These drives are conventional plater drives that add a small-capacity solid-state drive to the drive's controller. It behaves like an additional cache for frequently used files. It allows those files to be accessed more quickly because files are stored in the solid-state drive rather than the magnetic hard drive. It's not much different from taking a standard hard drive to be the primary storage of a computer system and adding a small solid-state drive as a cache through a system like the Intel Smart Response Technology.

A Closer Look

Because an SSHD is essentially the same as a conventional hard drive, but with additional space inside the drive to hold the solid-state cache, the SSHD offers roughly the same capacity as magnetic hard drives. The laptop and desktop variants of these drives ship with the same capacities.

The SSHD does cost slightly more than a magnetic hard drive because of the addition of the more expensive solid-state cache memory and additional firmware to control the caching processor. The prices range from about 10% to 20% more than a conventional drive.

The SSHD is cheaper than a full solid-state drive. For the capacities, an SSD costs anywhere from five to about twenty times the cost of an SSHD. The reason for this price disparity is that the higher capacity solid-state drives require more expensive NAND memory chips.

SSHD vs. SSD

The real test of a solid-state hybrid drive is in its performance compared to magnetic hard drives and solid-state drives.

The performance of any storage medium is a function of its most common use cases. Specs must be evaluated in light of how the hardware is employed.

SSHD performance depends on the amount of solid-state memory in the cache. SSHD drives may have 8 GB of this solid-state cache. The cache is a small amount that can be filled up quickly, requiring the frequent purging of the cached data by the system.

People who see the greatest benefit from these drives use their computers with a limited number of applications, such as browsing the web, reading and sending emails, and using a couple of productivity applications. A gamer who plays a variety of PC games won't see the same benefits as it takes several uses of the same files for the caching system to determine which files to store there. If files aren't used repeatedly, the solid-state cache benefit is limited.

SSHDs show an improvement over magnetic drives but not as significant as a pure-SSD solution. Beyond that, improvements prove much more variable. For example, when you copy a large amount of data, the cache overloads and the drive performs at the same level as a normal hard drive.

Who Should Consider an SSHD?

The primary market for a solid-state hybrid drive is laptop computers. The limited space on these systems generally prevents more than a single drive from being installed. A solid-state drive may provide lots of performance. However, the smaller sizes limit the amount of data that can be stored on an SSHD, and the price increases significantly the larger the SSD capacity.

As SSD prices have continued to fall, the market for SSHDs has shrunk dramatically. Now, a 1 TB SSD usually sells for around $100. Unless you need a large amount of storage, there probably isn't much need for an SSHD.

On the other hand, a magnetic hard drive offers lots of space but doesn't perform as well. An SSHD can offer an easy and affordable way to improve performance moderately without sacrificing storage capacity. SSHDs are best for people who are eager to upgrade an existing laptop system or want a compromise between the two extremes in a new system.

SAMSUNG 840 Pro Series 2.5-Inch 256 GB SATA 6GB/s Solid State Drive
Michael Saechang / CC BY-ND 2.0 / Flickr

For desktop systems, a combination of a small solid-state drive with a conventional hard drive likely offers greater performance improvements with only a slightly higher cost over an SSHD. The exception is the mini desktop PC that only has the space to fit a single mobile-size drive. These computers benefit in the same way as a laptop from an SSHD.