Solid State Drives (SSDs) are the lighting fast new kid on the hard drive block, but are they a good match for you? Read on as we demystify SSDs.
The last few years have seen a marked increase in the availability of SSDs and a decrease in price (although it certainly may not feel that way when comparing prices between SSDs and traditional HDDs). What is an SSD? In what ways do you benefit the most from paying the premium for an SSD? What, if anything, do you need to do differently with an SSD? Read on as we cut through the new-product-haze surrounding Solid State Drives.
What Is a Solid State Drive?
This might be hard to believe but Solid State Drives are actually fairly old technology. Solid State Drives have been around for decades in various forms, the earliest were RAM-based and were so cost prohibitive as to only make appearances in ultra high-end and super computers. In the 1990s Flash-based SSDs made an appearance but were again still far too expensive for the consumer market and made hardly a blip outside of specialized computing circles. Throughout the 2000s the price of flash memory continued to fall and by the end of the decade consumer Solid State Drives were making inroads in the personal computer market.
So what exactly is a Solid State Drive? First let’s highlight what a traditional Hard Disk Drive (HDD) is. A HDD is, at it’s most simple, a set of metal platters coated with a ferromagnetic material that spin on a spindle (much like a record spins on a turn table). The surface of the magnetic platters is written to by a little tiny mechanical arm (the actuator arm) with a very fine tip (the head). Data is stored by changing the polarity of the magnetic bits on the surface of the platters. It’s, of course, quite a bit more complicated than that but suffice to say that the analogy of an automatic record player arm seeking out a track on a record is not far flung from the actuator arm and head of a HDD seeking out data. When you want to write or read data from a magnetic HDD the platters spin, the head seeks, and the data is located. It’s as much a mechanical process as it is a digital one.
Solid State Drives, by contrast, have no moving parts. Although the scale is different and the size of the storage significantly larger, a Solid State Drive shares so much more in common with a simple portable flash drive than it does with a mechanical HDD (and certainly far more than it ever would with a record player!) The vast majority of the Solid State Drives on the market are of the NAND variety, a type of non-volatile memory that doesn’t require electricity to maintain data storage capacity (unlike the RAM in your computer which loses its stored data as soon as the power goes off). NAND memory also provides a significant increase in speed over mechanical hard drives as the time wasted spinning up and seeking is removed from the equation.
Comparing Solid State Drives to Traditional Hard Drives
It’s all well and good to have a handle on what Solid State Drives are but it’s even more helpful to compare them to the traditional hard drives you’ve been using for years now. Let’s look at a few key differences in a point-by-point comparison.
Spin-up Time: SSDs have no spin up time; the drive has no moving parts. HDDs have varying spin up times (usually a few seconds); when you hear a click-whirrrrrr for a moment or two when booting your computer or accessing an infrequently used drive you’re hearing the hard drive spin up.
Data Access Time and Latency: SSDs are lighting fast and generally seek on an order of 80-100 times faster than HDDs; by skipping the mechanical spin and seek routine they can access data almost instantly wherever it is on the disk. HDDs are hampered by the physical movement of the armature and the spinning of the platters.
Noise: SSDs are silent; no moving parts means no noise. HDDs range from pretty-darn-quiet to very-clumsy-click-beetle levels of sound.
Reliability: Individual manufacturing issues aside (bad drives, firmware issues, etc.) SSD drives come out ahead in the physical reliability department. The vast majority of HDD failures are a result of mechanical failure; at some point after X tens of thousands of hours of operation, a mechanical drive will simply wear out. In terms of read/write life, HDDs win (there is no write limit on a magnetic disk, you can change the polarity and indefinite number of times).
Conversely, Solid State Drives have a finite number of write cycles. This limited-write-cycle issue is much trumpeted by people decrying Solid State Drives but the reality is that the average computer user would be hard pressed to hit the ceiling of read-write cycles on a SSD. Intel’s X25-M drive, for example, can handle 20GB of data writing for 5 years without failure. How often do you erase and write 20GB of data to your primary disk on a daily basis?
Additionally, SSD drives have a pretty neat-o feature; when the sectors of the NAND modules reach the end of their write-cycle they become read only. The drive then reads the data from the failed sector and rewrites it a new portion of the disk. Barring a lighting bolt or a catastrophic design flaw, SSD failure looks more like “Oh the old age, why, the aching in my bones!” and not the more dramatic “BOOM! My bearings have seized!” failure that comes with mechanical hard drive failure. You’ll have plenty of time to backup your data and procure a new drive.
Power Consumption: SSD drives consume 30-60% less energy than traditional HDDs. Saving an odd 6 or 10 watts here and there doesn’t seem like a lot but over the course of a year or two on a heavily used machine it adds up.
Cost: SSD are not cheap. Traditional HDD prices have fallen to roughly a nickel per GB of data. That’s astonishingly cheap by historical standards. SSDs are much cheaper than they were 10-20 years ago (when they were limited to specialty computer systems) but they’re still quite expensive. Depending on the size and model, expect to pay anywhere between $1.25-$2.00 per GB as of the writing of this article (March 2011).
The Care and Feeding of a Solid State Drive
In so far as running your operating system, saving data, and interacting with your computer goes the only difference you’ll notice as the end user, while running a SSD drive, is the increase in speed. When it comes to taking care of your drive, however, there are a few rules of critical importance.
Don’t defragment your drive. Defragmentation is useless on a SSD and it decreases the lifespan. Defragmentation is a technique that brings the pieces of files closer together and optimizes their placement on the platters of HDDs to decrease the seek time and the wear and tear on the disk. SSDs have no platters and have a nearly instantaneous seek time. All defragging them does is chew up more of your write cycles. By default in Windows 7, defragmentation is disabled for SSDs.
Turn off Indexing Services: If your OS rocks any sort of search-supplementation tool like an Indexing Service (Windows does), turn it off. The read time is so fast on SSDs that you don’t really need to build a file index and the actual process of indexing the drive and writing the index is slow on SSDs.
Your OS should support TRIM. The TRIM command allows your OS to communicate with your SSD drive and tell it which blocks are no longer in use (and are thus clear for wiping). Without the TRIM command taking care of some housekeeping on your SSD the performance will rapidly degrade. As of this publication Windows 7, Mac OS X 10.6.6+ and Linux Kernel 2.6.33+, support the TRIM command. While registry hacks and supplementary programs exist for modifying earlier OS versions like Windows XP to semi-support the TRIM command there is no native support. Your SSD should be paired with a modern OS for maximum performance.
Leave a portion of the disk empty. Check the specs for your drive, most manufacturers recommend keeping 10-20% of the drive empty. This empty space is there to assist the leveling algorithms (they redistribute the data across the NAND modules to minimize the total wear on the drive and ensure a long life and optimum drive performance). Too little space and the leveling algorithms work over time and prematurely wear on the drive.
Store media on a second drive: Until SSDs drop radically in price it makes no sense to store your massive media files on your expensive SSD. You can pick up 1TB traditional HDDs for under $100 now; use a large secondary drive (when possible) for storing your large and static files (such as movies, music collections, and other media files).
Invest in RAM: Compared to the cost of Solid State Disks, RAM is cheap. The more RAM you have the less writes-to-disk you’ll have on your OS disk. You’ll extend the life of your pricey SSD by ensuring your system has adequate RAM installed.
Is a Solid State Drive for You?
At this point you’ve got a history lesson, a point-by-point comparison, and some tips for keeping your SSD in tip-top shape, but is an SSD for you? Check all that apply and get ready to bust out your credit card:
* You want nearly instant boot times: You can go from a cold boot to browsing the web in a matter of seconds with an SSD; the same window is often minutes with a traditional HDD.
* You want extremely fast access for general applications and gaming: We’ve said it many times already but SSDs are blistering fast.
* You want a quieter and less power hungry computer: As highlighted above, SSDs are silent and use significantly less power.
* You’re able to use two drives; one for your OS and one for your media: Unless you’re storing just a handful of family pictures and a CD rip or two, you’ll need a more affordable traditional HDD to store your big files.
* You’re willing to pay a significant premium for the benefits of rocking an SSD: This is the biggest one by far as the premium per GB is currently around 3000%. While the performance increase is enormous 3000% more per GB is nothing to sneeze at.
If your checklist looks more full than empty and you scoff at a mere 3000% premium in exchange for rocking the speediest disk around, congratulations an SSD is for you!
Courtesy of HTG:
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