Solid State Drives: An Objective Comparison to HDDs

Posted on 01/23/2015 by

Tien Shiah

More from the Samsung and Dell Tech Center blog series:

Solid State Drives (SSDs) and hard disk drives (HDDs) do the same basic job: each stores data. They contain operating systems, applications, and store personal files. But each uses fundamentally different technology to accomplish the same tasks.

What’s the difference?

To answer the first question, HDDs use rapidly rotating platters of magnetic media to store data. This technology dates back to 1956, and it’s been refined over decades to be the default storage medium for desktops and laptops. On the other hand, SSDs have no moving parts, using integrated circuit as memory to store data. Though tested and proven for more than a decade, SSDs still aren’t as common.

Why would a user choose one over the other? Well, each technology has its advantages depending on the factors that are important to you.

Price: To put it bluntly, in terms of dollars per gigabyte (unit of storage), SSDs are more expensive. As of October 2014, a 500GB SSD retails for $269.00, while a 500GB hard drive retails for $64.99. That translates into $0.53/GB for the solid state drive, and $0.12/GB for the hard drive. Smaller SSD drives are more cost-effective, but for the most part, a price gap remains between SSD and HDD, though SSD prices have declined significantly over the past few years.

Capacity:  SSDs have another perceived challenge. Basically, the more storage capacity, the more data and applications (programs, photos, music, videos, etc.) a PC can hold. At the moment, Samsung offers a range of PC SSDs up to 1TB. But hard drives offer much larger capacities, up to 4TB. Realistically, however, for many business users this capacity discrepancy isn’t an issue because they would struggle to fill a smaller drive, much less a terabyte. It would only become an issue for anyone who handles large numbers of large files, such as heavy multimedia users or graphic designers.

So why choose SSDs?

Performance: Mainly, it comes down to performance. In one test conducted by an independent third party, a Samsung 840 EVO SSD completed a Windows boot cycle in 18 seconds, while the same laptop using a standard 7200RPM hard drive took over a minute (1:11) to perform the same task. Other tasks, include application launches and shutdowns show a similar performance boost. Normal operation also becomes faster so system responsiveness improves. Whatever the use, this extra speed may be the difference between finishing on time and failing to, and it certainly leads to better user satisfaction over time.

Durability: Solid State Drives offer a compelling durability advantage. With no moving parts, a SSD is more likely to preserve data in the event of impacts of physical damage. Most hard drives park their read/write heads when the system is off, but they are flying over the drive platter at hundreds of miles an hour when they are in operation. That basic capability makes SSDs fundamentally valuable for anyone who travels with their laptop or works in an environment with vibration or physical shocks, like a factory floor.

Fragmentation: Because of their rotary recording surfaces, HDD surfaces work best with larger files that are laid down in contiguous blocks. That way, the drive head can start and end its read in one continuous motion. When hard drives start to fill up, large files can become scattered around the disk platter, known as fragmentation. HDDs fragmentation causes system performance degradation over time, while SSDs, using solid state memory, don’t have this limitation. Since there’s no physical read head, SSD performance doesn’t decay due to fragmentation.

Heat and Power: Because HDDs rely on spinning platters, they consume more power than HDDs, which causes them to emit more heat, resulting in additional cooling needs. For desktops, few people care, but for laptops, which run on batteries, the power consumption difference matters. Some of the most power efficient SSDs are made by Samsung, consuming as little as 0.045W at idle. Also, since SSDs are so much faster, they finish tasks quickly, reducing the time spent at peak power consumption.

Noise: Even the quietest HDD makes noise. Noise comes from the drive spinning or the read arm moving back and forth. Faster hard drives make more noise than slower ones. SSDs make virtually no noise at all, since they have no moving parts.

Longevity: There’s a lot of discussion around longevity, but under average commercial workloads, a typical client SSD will last over 16 years.  That’s because SSDs have adopted a range of maintenance technologies to ensure data integrity, bad block management, error correcting code, and wear leveling. It’s possible that HDDs could have a longer lifespan, but for most users, the longevity difference is a moot point that won’t matter in real life, especially if impact resistance is taken into account.

What’s the conclusion?

Overall, HDDs currently hold an advantage on price and capacity. SSDs work best if speed, ruggedness, power/cooling, noise, or fragmentation (technically also part of speed) are important factors. If it weren’t for the price difference, SSDs would be the winner hands down. Regardless, for many users, the benefits of SSDs outweigh the few advantages still held by HDDs.

Samsung, the world’s leading supplier of SSDs, offers a broad portfolio covering all of your capacity, form-factor, and interface needs.

For more information, please visit: http://www.samsung.com/global/business/semiconductor/product/flash-ssd/overview

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