SSDs: Redefining Storage Performance

Hardly a week goes by without some new SSD product release, and the market remains in a rather volatile state, both despite and because of this continuing growth. Solid state drives come and go, but there are a precious few, such as Intel, that deservedly stick around.  Similarly, controller vendors, including JMicron, Indilinx, and SandForce, have been making impressive progress.

This article originally appeared here on Tom’s Hardware. It has been edited for the busy IT pro. Please see the original for details excluded here and for information on how to buy products featured herein.

Just How Fast Are SSDs and Why?

That SSDs can beat the pants off hard drives isn’t exactly news anymore. Tech enthusiasts and IT personnel also understand the value of 200+ MB/s performance, low power consumption, and physical robustness along with the potential pitfalls of older operating systems. Real tech addicts will go into the nitty gritty of I/O performance, power efficiency, and architectural details on caching, wear leveling, TRIM, and RAID support. These details can make a significant difference on the performance side of storage.

You won’t find performance comparison for SSDs in this article; for that, check out our most recent SSD benchmarks.

When discussing SSD performance, it’s important to define what performance actually means. The term is either used to measure speed or to look at metrics like power consumption, efficiency, or performance per watt. In the storage segment, capacity per dollar or per watt can be key metrics, while top-performance systems, particularly in enterprises, can benefit from high I/O performance per watt.

Samsung states a 10% to 35% increase in I/O performance thanks to double data rate (DDR) NAND flash. Also, keep in mind that you will not see more throughput, but the number of individual transactions could increase.  Most SSDs are based on multi-channel architectures that combine various flash memory lines to maximize performance. Because of this, increasing interface bandwidth might not always be necessary. The only item left to improve is the flash memory itself.

Consumers will look at throughput numbers first, which range anywhere from 180 to more than 300 MB/s for sequential read operations and 80 to 300 MB/s for writes. Most products are limited by the SATA 3Gb/s interface to less than 300 MB/s peak performance, but even the few drives available with 6 Gb/s interfaces aren’t always the best choice, since their I/O performance doesn’t scale with interface bandwidth. All the horsepower in the world doesn’t matter if you’re stuck at an intersection.

SSD or HDD?

It is important to note that there are faster and somewhat more efficient hard drives available. Yet, performance differences are significant enough to be sure that whatever you tweak on the hard drive side still cannot beat a fast and efficient SSD array. Although SSDs based on the DDR technology are available, test results can be considered representative for modern SSDs in general. We've seen up to 12x faster performance in I/O operations, and power efficiency can increase many times if you look at it on a system level—even more if you simply compare data on a drive level.

In the end, you should decide whether it’s time to adopt SSDs over HDDs by examining the scenarios in which hard drives still make sense. Mission critical systems may have strict validation requirements. There could be cost or capacity conditions placed on a configuration that take precedence over I/O performance.

From Samsung data, SSDs are getting close to roughly 10% share in NAND flash memory utilization. The projection shows SSD becoming almost 20% of the NAND flash market by 2012. The only other segment that should see even larger growth is ultramobile devices, such as tablets and smartphones. 

From a cost point of view, $699 for a high-end 256 GB SSD is still a lot compared to less than $300 for a very fast 15 000 RPM, 300 GB SAS hard drive. But $399 is reasonable for such a fast 128 GB SSD. However, once you start consolidating storage systems, recognize the long-term power savings, and are able to get potentially more work done in far less time, owning a smaller number of SSD-centric machines start to get seriously attractive.

Patrick Schmid is VP Worldwide Development, Tom's Hardware at Bestofmedia Group.

Achim Roos is Test Editor at Tom's Hardware Germany. He is a certified engineer who develops benchmarks and performs testing on CPUs, all kinds of storage, and platforms