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HTG Explains: What’s a Solid State Drive and What Do I Need to Know?

2011-03-08_110215

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

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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

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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 Me?

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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!


Have your own SSD experiences, tips, or tricks to add? Let’s hear about them in the comments. Questions? We want to hear those too!

Jason Fitzpatrick is warranty-voiding DIYer and all around geek. When he's not documenting mods and hacks he's doing his best to make sure a generation of college students graduate knowing they should put their pants on one leg at a time and go on to greatness, just like Bruce Dickinson. You can follow him on if you'd like.

  • Published 03/8/11

Comments (40)

  1. MJ

    Great article.

  2. Chris Mathews

    “…SSDs are much cheaper than they were 1020 years ago…” Now that’s old school!n William the Conqueror used SSD drives.

  3. Chris Hunter

    Really great article.

    What size SSD do you recommend if I want to replace the HDD in my laptop with me running Windows 7? Is 64GB enough or do I need at least 128GB?

    Thanks for the help!

    Chris

  4. Demonkunga

    Depends on how much data you have Chris. I have a 64 GB myself. But I also only have small applications, 2 games, and 5 GB of music. (I store my movies on another computers hard drive).

  5. Mastermind

    “SSDs are much cheaper than they were 1020 years ago”

    Shouldn’t this be ’10-20′ ?

  6. Chris Hunter

    Yeah, I’m wanting to use an SSD for my OS and use an HDD for file storage. I just wanted to know how big my OS SSD should for Windows 7 primarily. I don’t really think that it uses 64GB, does it?

    Chris

  7. richard

    @chris hunter: look if you would have enough space on your laptop now.
    on my desktop pc my c drive with win7 have approx. 40gb and my d drive with programs additonal 17gb. my data drive is not included.
    for a laptop i would recomend 128gb but as i said it depends on your usage

  8. duquesne

    it says to turn off indexing services but OS X indexes by default as well. is there an option to disable it? because on 1st boot after install, it starts indexing automatically. or will the OS be able to recognize it as an SSD and not index? or will this be implemented in future updates (10.6.8? or 10.7)

  9. Haddicus

    WORD OF WARNING! I know several people go solid state this year, and regret it! If you do go solid state, make sure you have a very optimal backup strategy in place taking place daily! I know too many people who have lost data due to moving over to SSD. If it dies, you are hosed!

  10. Chris Hunter

    @Richard – Thanks for the info. See, I currently have everything on a 320GB HDD right now, but I want to “power up” my OS with an SSD.

    I think that a 128GB would suffice and I could still use an extra HDD for storage. Even considering a 256GB SSD as well.

    Thanks!

    Chris

  11. Jason Fitzpatrick

    @Chris Matthews: I think that is the most awesome typo I have ever made.

    @Chris Hunter: I’ve been bit by the SSD bug myself and plan on upgrading soon. I currently have an 80GB Raptor as my primary Windows 7 drive… I find it a bit tight. When I upgrade to an SSD I think 128GB is the sweet spot for my needs. I could get by with an 80GB but I’d rather be comfortable and have extra room for the drives leveling algorithms.

  12. Albania-n

    greate article , very informative.

  13. Deniz Zeybek

    @ Haddicus

    I just can’t see that conclusion with the one in the article. What do you mean by “if it dies”, a HDD could also die and you will lose all your data. Please enlighten me :)

  14. Jon

    I don’t agree with some of this article. Hard drives don’t wear out over time. Modern drives use FDB motors and generally it isn’t the motor that goes on modern drives. It is generally the controller board due to heat problems. Keep your drives cool and they should last forever. The MTBF for a Samsung HDD is 500,000 hours. Do the math. That’s 57 years.

    Also, regarding power draw, most drives are not using full power all the time. So at idle you are looking at a 3-4W difference at most. That’s going to be a whopping $3-4 per year difference depending on where you live and the cost per kWH.

    Consider the cost difference per gigabyte and you save LOADS more by going with a HDD over a SSD.

  15. strav

    What is your opinon about the Paging file? I’m debating whether to resize it and/or move it.

  16. miki

    I buy an ocz revo drive…it have an extreme speed, because use pci-express bus!
    Standard hdd is the real bottle nec in modern pc.
    120GB for 250€

    My pc now fly !!

  17. Trevor Bullement

    Hi having seen somewhere that there are 2 types of SSD single layer/dual layer
    which do you advice. Thankyou in advance.

  18. Edward Allen Weissbard

    I was wondering if it is possible to create an image of your OS environment from a SSD and backup to a traditional HHD?

  19. Bill

    Be careful quoting MTBF figures… 500,000 hours doesn’t mean a drive should last 57 years, it means if you run 57 drives for a year, you
    accumulate nearly 500,000 hours… if only one drive fails – mfr can say MTBF = 500,000.

  20. meh

    Something missing here, lets say while ur playing with your computer on a rainy day and electric raised and shiiit your computer is gone
    what to do?
    u may get your data back by simply changing your hdds pcb
    but if your all data is on SSD you have a bunch of fried chips that you can never get your data back

  21. Rob50

    You always need some type of backup if you decide to use a SSD drive, for obvious reasons if the drive fails, no data recovery place in the world can recover your data from a SSD with fried chips. Like a HDD it is always the best policy to have some type of back up plan to back up your data, it is even more critical with a SSD drive.

  22. Lucky

    I put a 128GB SSD in my laptop with Win7 on it. The performance blew me away. I bought another one to put in my wife’s laptop. We have been running them for about 6 months now and will NEVER go back to a HDD except for storage. One thing I would like to point out in my case; they seem to use the same amount of power. I was hoping to get a little better battery life in our laptops, but its about the same. I have the Kingston SSD now v2 which isn’t the fastest SSD, but they have a good reliability rating.

  23. Odin

    @meh

    lets say you are playing with ur pc while an earthquake hits your house, your HDD gets out of control and the disk goes flying trough your room decapitating you on its way… head and data gone..!

  24. Bill Botzong

    I changed my main drive to a 256gb SSD and have FINALLY gotten the performance from my computer that CPU, motherboard and RAM updates have always failed to provide. I go from sleep to boot in about 3 seconds. I go from complete power off to ready-to-use in about 25 seconds. I have two SSDs where I put the bulk of my program and system files. I have a 1T hard drive for media files, etc. I just can’t tell you how much of a speed increase I’ve had with SSD. In my opinion, it is the single biggest change you can make to speed up your system. True, they’re still pricey. But, I found my 256Gig on eBay and got it for a substantial discount because it was OEM.

    One other thing, I heard you cannot RAID your SSDs because that disables the TRIM function. Don’t know if that’s true, but it has been relatively easy to change the c:\ prompt to r:\ (my second SSD) when installing apps. This leave about 40% free on my main drive and about 20% on my secondary drive.

  25. Thomas Clover

    I have been really interested in the SSDs for quite a while and will pick one up as soon as the price drops a little more. I have read quite a few articles on the subject and I see no reason to move the swap file to a separate disk. Your performance might actually suffer, unless the other drive is also a SSD which would defeat the purpose of moving the swap file. As long as you have as much RAM as your OS and motherboard can reasonably support, you should be golden.

  26. mmth42

    I use SSDs extensively. My only negative comment about them is that my first, a very expensive 64g one, died after a few months of use. It didn’t get stepped on or even dropped, but its data simply became inaccessible one day, and of course it could no longer be written to. The others I have, ranging from 4gb to 32gb, are still with me after a year, so I trust they’ve improved. I have another 64 on a shelf waiting till I need it, and I would love it if my 2009 HP could use SSDs exclusively. With its 4gb of RAM, it takes Windows 7 about 15 minutes to boot up to the point where it can be used. And unlike Home XP, the Professional 64-bit version has no “hibernate” mode, so it has to either doze or shut down.

  27. Johnathan

    There are options to add one SSD to another SSD without RAIDing them. Just as there has always been that option with NTFS. create the partition without assigning a drive letter. MOUNT that partition into an EMPTY NTFS folder on any drive – voila!! you have that drive space available to the first drive letter without clutter of drive letters and still supporting the TRIM function. Also, for those that are advanced enough to figure it out, without me creating a walk-through here, it is possible to make this MOUNTed NTFS partition become the (c:\program files\ ) folder directory. With x64 windows this is more difficult as there are two default locations (c:\program files\) and ( c:\program files(x86) ). However, the more common at the moment is (c:\program files(x86) ) and this would be the one to accomplish this trick with. I have done this with many home-built computers, which saves the remembering to change the install path of the program being installed.

  28. Craig

    I put a 128 gig ssd in my older toshiba laptop with a dual core non hyper threaded chip,win 7X64, and watched my boot time drop from several minutes to 20 seconds including typing in my password! I use my ssd laptop for travel and I would never even consider another laptop without one! I expect my current ssd to out live me!!!

  29. John Gemper

    My question is about USB Flash Drive which is a very close relative of SSDs. Please correct me if I am wrong, but I believe that the charge in a NAND which defines its bit state leaks over time. Question : How long after the last “write” operation will a NAND retain enough charge that its bit state can be read correctly?

  30. Santo

    Well written article.

  31. rino

    so how does one come up with the numbers that most users will not hit the SSD write ceiling? generally speaking? what about gamers?

  32. Wisdom

    ssd is for a os only, 64gb are everything that you ever need, aprox next 5-6 years, so get 1 with most quality and speed. there is a fast, faster and most faster ssd drive. i have 1 over a year now and there is no way to get back on standard hdd drive, for os and application ofc.

  33. Adam

    I have no problems with the regular HDD format. I use 1TB drives. If you are going to boot on a SSD but keep the files on a regular plate HDD, I see no real advantage. SSD break more often that plate drives. They are more affected by humidity, static electricity, and others.
    If they make 2TB SSD drives and sell them for the price of a traditional HDD, I will think about them.

  34. Kainon

    SSD Drive is redundant. Solid State Drive Drive?

  35. VW

    Not too thrilled by SSDs personally I bought one it took forty minutes more to install fedora 14 and had a boot time of about 10 minutes, so I brought it back, after testing Win7 and Ubuntu, thinking it maybe faulty exchanged it in store for a new one of a different brand I got the same results so I took it back and exchanged the 128GB SSD for a 1TB HDD and now I have a boot of one minute thirty five seconds and it only took 20 minutes to install fedora so again not to thrilled by it. My linux machine has 4GB of RAM so that isn’t an issue.

    Adam I agree with you on the effects of the environment on an SSD, only thing you have to really worry about day to day with a traditional HDD is the drive controller over heating or some kid playing with a substantial magnet.

  36. Peter Kowarik

    How does one format then portion a SSD with win 7

    Thanks

  37. Ken

    Curious there was no mention of hybrid SSD/ HDDs here. Especially for notebook use, which might be the biggest market for SSDs due to longer battery life. I like the idea of having an SSD for the OS and all my programs, but all data stored on a backed up HDD. Great performance increase and less wear on the SSD, but most laptops cant accomodate that, until the hybrid drive. On a desktop, the Sky is the limit. By the way, anyone who can afford to put an SSD in anything, shouldn’t you already be running on a surge protector? A REAL one!!!

  38. pinky

    Has anyone tried to encrypt a SSD before?

  39. J.W

    Do the SSDs make gaming better?

  40. Justin

    @ken

    just bought a lenovo idea pad ssd/hdd rapiddrive combo. It’s pretty awesome. it has 32 gb’s of SSD and 500 of HDD. It reads what programs i use most and tranfers them from the hdd to the ssd if they arent already on the ssd. It’s a beauty, i don;t have to tranfser anythign myself, it takes care of it for me.

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