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Understanding the basics of SSD drives

Discussion in 'Apple' started by Ronald Epstein, Sep 13, 2012.

  1. Ronald Epstein

    Ronald Epstein Administrator
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    I suppose I have much to learn about SSD drives.

    All I can tell you is that after having one in my MBPr,
    I will never go back to a hard drive.

    I am anxiously hoping that Apple still has new iMacs to
    announce by year end and that purchase will also include
    an SSD drive.

    I really don't know much about SSD drives and once in
    a while I come across statements on other forums like
    "the more you write to an SSD drive the more it slows down."

    I believe I have heard a few hints here on this forum that
    it's not good to constantly write to SSD drives.

    On my laptop it's no problem. I don't do much file downloading
    or document editing or otherwise. All I do is browse and email.

    However, on my next iMac, all I will be doing is downloading
    files, editing documents and constantly editing (adding and deleting)
    things.

    Would it be better to add an external drive for all the things I
    need to write, edit to and delete?
     
  2. Craig S

    Craig S Premium
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    Ron, the current iMacs (and I assume the coming new models) have the SSD as a second internal drive. I'm pretty sure that if you configure the SSD it is set up as the boot drive, holding the OS and your applications. There will be a 2nd internal drive, a regular 7200 RPM hard drive (as big as 2 TB) which is where you will store your data.

    With this setup, your daily heavy read-write work will be against the regular HD. The SSD will be mainly read (running the OS, launching apps), with writing happening mainly during OS updates and app installs and updates.

    That said, based on your posts here I'm pretty familiar with how long you hold onto your machines and I doubt you would have any problems "wearing out" your SSD with any kind of normal day-to-usage before you would naturally upgrade your machine anyway.

    In other words - don't sweat it. SSDs are awesome. Buy and enjoy!

    Oh yes - you will want an external drive anyway - for local BACKUP!!!
     
  3. Ronald Epstein

    Ronald Epstein Administrator
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    Craig,

    I am a big believer of external drives. I do backup at least once a month.

    But on my desktop, I am constantly downloading, deleting, installing, uninstalling,
    writing, rewriting, etc.

    Daily and heavily.

    Glad to see that you think I'll be okay with an SSD drive. Not interested in
    amending my current iMac, but looking forward to a new one.
     
  4. Thomas Newton

    Thomas Newton Well-Known Member

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    It's more like, "the more you rewrite files on a SSD (especially a nearly full one), the more it slows down."
    A hard disk has to physically move heads around to get to the various parts of a file. So what really kills performance is when the parts of the file are scattered all over the place.
    A SSD uses flash memory. You can't reuse a location in flash memory unless you erase the entire sector containing it. That is slow, and the sectors are huge compared to hard drive ones (maybe 8KB to 32KB for flash, compared to 512 bytes for a HD). Suppose that your operating system manages SSDs as if they were HDs, and wants to write 512 bytes of data to a previously-used spot on a SSD. Now it has to:
    1. Read the contents of the entire flash sector into memory
    2. Erase the sector
    3. Write back the portion of the data in #1 that corresponds to files that still exist
    4. Write the small amount of data that it wanted to write in the first place
    Vendors have been working on ways of mitigating this problem, but this is to SSDs what fragmentation is to HDs.
     
  5. Ronald Epstein

    Ronald Epstein Administrator
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    Thomas,

    So what do you think?
    As someone that does a lot of rewriting on my desktop, ultimately, will
    I benefit from an SSD drive?
     
  6. Thomas Newton

    Thomas Newton Well-Known Member

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    Don't worry too much. I was just trying to provide a little of the "why" behind statements like "writes make SSDs slow down". (If you know the "why", you can figure out, for instance, that running traditional hard disk defragmenters on SSDs is generally a Bad Idea.)
    Let's say you had your OS and applications on your SSD, to speed up "cold booting" and application launch. Even if you wrote and erased and rewrote so much that writes slowed down, you'd continue to see improvement in "cold boot" and application launch times.
    I'm sure you are already aware of two "tricks" to avoid startup delays: putting your Mac to Sleep (instead of shutting it down) when you may use it in the near future; and keeping applications open. Those produce a nice gain even on hard-disk-based iMacs – so it may be hard for a SSD to provide a lot more further improvement. Since you've used both a HD-equipped iMac and a SSD-equipped MBP, you have probably already taken this into account in forming your opinion of SSDs:
    If I was ordering for myself, the decision I'd be looking at next is whether to order the SSD from Apple, or to order it from Other World Computing (and have them do the installation). OWC has a wider range of SSD sizes (80 GB to 480 GB, versus Apple's 256 GB), and they claim that their "6G" SSDs have features to help maintain high performance over time. They will install up to three SSDs (although that sounds to me like overkill; a SSD + HD combo would probably serve you better). On the other hand, I don't know how such an aftermarket upgrade would affect the warranty.
     
  7. Ronald Epstein

    Ronald Epstein Administrator
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    Quote:

    How would they do the installation?
    You aren't suggesting I send them my iMac.
     
  8. Thomas Newton

    Thomas Newton Well-Known Member

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    That was their suggestion, on the "Turnkey Upgrade Service" pages. They do sell the internal SSDs as parts, so if there was a repair shop in your area qualified to work on the inside of an iMac, you could buy a SSD from OWC and have your local repair shop install it. It's just that on an iMac, the RAM is the only internal part that is user-serviceable. They don't recommend that you try to install a SSD inside the case yourself – there's presumably less chance of something going wrong if they or some other shop do the installation.
    If that's not attractive, there's always the internal Apple SSD. No muss, no fuss, as long as you custom-configure it at order time.
    Also, Thunderbolt and USB 3.0 theoretically should allow for decent performance from external SSDs.
     
  9. Ronald Epstein

    Ronald Epstein Administrator
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    Thomas,

    Thank you so for the help and suggestions....

    ...now just waiting on Apple to announce new iMacs.
     
  10. Adam Lenhardt

    Adam Lenhardt Well-Known Member

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    I've been running my Windows 7 desktop with a SSD as my boot drive since February. You can read about my experiences in this thread: http://www.hometheaterforum.com/t/318227/ssd-as-boot-drive
    Basically, the computer had shipped with a 1 TB traditional SATA harddisk. I'd later installed a 500 GB traditional SATA harddisk. I backed up everything from the 1 TB drive and wiped it clean, leaving the 500 GB harddisk untouched. The SSD I went with is a Crucial M4 CT128M4SSD2 2.5" 128GB SATA III MLC Internal Solid State Drive (SSD), which I mounted using a $7 2.5-inch SSD to 3.5-inch Bracket Mount Adapter.
    Solid state drives have a high burn-out rate, so the ONLY thing I keep on the SSD is my Windows installation and my installed programs. Everything else -- my libraries, my documents, even my desktop and temporary files -- go on the 1 TB drive. The first thing I did once I had everything installed was make a disk image of the entire SSD. That way there, if it craps out I can reinstall the image on a new 128 GB harddisk and be back in business very quickly.
    Even with the greater risks with a SSD, I'd never go back. The user experience, particularly for booting up the computer and shutting it down, has been pretty night-and-day for me.
     
  11. Ronald Epstein

    Ronald Epstein Administrator
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    Wow. The more I hear about this, the more I wonder the benefits
    beyond faster boot and app launch.

    Sounds like I should get a small SSD drive and then add on a
    permanent spinning hard drive to copy and write folders too.

    Was hoping this would have been better than I initially hoped.
     
  12. Thomas Newton

    Thomas Newton Well-Known Member

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    There are SSDs made with endurance in mind. These usually have the words "industrial" or "data center" somewhere in their descriptions. For instance, Intel has the "Solid-State Drive 710" series (SATA form factor), which they describe as "a high-endurance SSD designed for data center performance", and the "910" series (where the SSDs are in the form of PCIe cards).
    http://www.intel.com/content/www/us/en/solid-state-drives/solid-state-drives-710-series.html
    These come in 100, 200, and 300 GB sizes, but are not cheap. The 300 GB one costs $1225 on Amazon (if purchased from Amazon.com and not some Marketplace dealer); even the 100 GB one is $400.
    For the 710 series, Intel specifies write endurance in terms of how many petabytes or hundreds of terabytes can be written. If you go a step down to the 520 series, which Intel does not certify for data center use, Intel claims that "The SSD will have a minimum of five years of useful life under typical client workloads with up to 20 GB of host writes per day." But on Amazon, an Intel Series 520 SSD (480 GB, SATA Reseller Kit – just one of several sizes) goes for $500. (That is, about $1 a GB for a "client" SSD as compared to $4 a GB for a "data center" one.)
    By the way, the Intel 520 might be another SSD to consider as an alternative to the Apple one. The reviews on Amazon were glowing.
    http://www.amazon.com/Intel-Solid-State-Drive-SATA-2-5-Inch/dp/B006VCPA1A/ref=sr_1_4?s=electronics&ie=UTF8&qid=1347748766&sr=1-4&keywords=Intel+SSD+520
    So I looked up these others on AnandTech, Tom's Hardware, and Engadget:
    http://www.anandtech.com/show/5508/intel-ssd-520-review-cherryville-brings-reliability-to-sandforce
    http://www.tomshardware.com/reviews/ssd-520-sandforce-review-benchmark,3124.html
    http://www.engadget.com/2012/02/06/intel-ssd-520-review-roundup-intel-reliability-sandforce-speed/
    One interesting thing is that Intel offers a 5-year warranty on the 520 (a warranty that they don't offer on their data center SSDs). They must be betting that an average SSD buyer won't be likely to "burn out" a 520 faster than that.
     
  13. HDvision

    HDvision Well-Known Member

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    Yes Ron, I run a SSD with only the OS, all my data goes to a regular drive except for instant workfiles. That way if your SSD gives up, you only lose your OS. All your data is old school safe.
     
  14. Sam Posten

    Sam Posten Moderator
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    Without being condescending Ron I believe you are overthinking it and the 'scare' of burn out due to churn is nothing that you will experience in an ordinary gadget lifetime. Especially given that you tend to upgrade on a pretty regular basis.
    On the other hand I am not a big fan of either of the following:
    -Adding SSDs to laptops that were not designed for them from the start (even on my Alienwares it is somewhat tricky to do a replacement due to BIOS issues)
    -Using SSDs as media drives, their benefits wane if not being used as an OS and Application center.
     
  15. Ronald Epstein

    Ronald Epstein Administrator
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    Appreciate that Sam.

    I will probably use an external drive, however, for most of
    the rewriting I expect to do.

    Let's keep our fingers crossed tomorrow is the day for iMacs.

    (Don't know why I am even really investing hope that it will be)
     
  16. JohnRice

    JohnRice Well-Known Member

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    Ron, the best answer does seem to be using the SSD only for the OS and Apps. With any other type of files there isn't as much of a benefit to SSD over the highest speed disc HD you can get. As you know, I have been using an external SSD this way for a few months now and I get a noticeable all-around speed boost. This seems to be because the OS is constantly needing to reference thousands of tiny files.
    After all, the OS has over 600,000 files to it. SSDs access these so much faster. The rather limited bandwidth of FireWire 800 doesn't slow the process down as much as you might think, since pure bandwidth isn't as important with OS processes as latency, which is virtually non existent with SSDs. Not to say an internal SATA III connection wouldn't improve things further, just not as much as you'd think. For a while I had another SSD connected mainly to read and write media files and the speed improvement for that was rather small. Not really worth the cost and shorter life of the SSD.
     
  17. Ronald Epstein

    Ronald Epstein Administrator
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    John,

    I appreciate your words here.

    Let me explain why I am looking to spend extra for an
    SSD drive in my next iMac....

    First, of course, I am looking for my computer to instantly
    boot up -- as instantly as an SSD can over a standard HD.

    Next, application launch time. When I launch Photoshop
    I want it to instantly pop up (as it does on my MBPr).

    Everything else I don't mind if it eventually slows up.

    The big question is whether it is worth writing, copying
    and deleting files on my SSD on a daily basis and what
    kind of harm that could do to the overall performance of
    my boot and application launch time.

    Thanks
     
  18. Adam Lenhardt

    Adam Lenhardt Well-Known Member

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    I can tell you that with my setup the boot and shutdown times have been night and day since I switched to a SSD for my OS and applications. I've experienced no real issues with storing my files on a standard 1 TB hard drive. I'm a Windows user, and it took a little doing to convince Windows 7 to put all of my libraries and documents folders on the one drive while the operating system and program files were on another, but once I'd gotten it setup, it's been utterly transparent for a user experience. Overall speed across the entire system is noticeably faster. Photoshop loads in around 5 seconds, where it used to take closer to half a minute when it was loading off the 1 TB drive.
     
  19. JohnRice

    JohnRice Well-Known Member

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    I've had a similar improvement. It also wasn't as big a change in procedure for me because I have had my files essentially split up across drives this way for years. I did trim the boot drive a bit, but not that much. I actually use several drives, each prioritized based on how important the data is. The boot drive and primary file drive are backed up frequently. Then I have a media drive that is dedicated to files I also need backed up and finally a "temporary" drive with mostly video files that I don't back up. Not that anyone asked.
     
  20. JohnRice

    JohnRice Well-Known Member

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    Ron, I thought you might be interested in what I am going to try next week. First, since I have as many as 5 Macs to upgrade in the next few months and at least 3 of them don't really need to have USB 3, I went ahead and got the current Mini to upgrade my home one. It is almost double the speed of what I have and can easily have RAM added, both which I wanted. Once new models come out, it will go to the office and I'll get whatever has a quad core. Anyway...
    With all the issues of SSDs, the prices Apple charges, their possibly short life and so on, I decided to order a Refurb Lacie 2Big 4TB external Thunderbolt drive. The $300 price is really an excellent deal, so long as the thing isn't defective. The TB bus speed is significantly faster than SATA, so I should get maximum speed. I decided on this particular model because I can remove one drive and install an SSD (in a 2.5>3.5 housing) without voiding the warranty. Then in that housing I get a maximum speed SSD boot drive as well as a 2TB "scratch" drive for the video and image files I am constantly processing. There's even an extra 2TB drive which I'll probably use to backup my media server in another housing. I like that this gives me a lot more versatility than internal drives. Hopefully it will work out well.
     

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