SSD Buying Guide

Discussion in 'MacBook Pro' started by Hellhammer, Jun 25, 2011.

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  1. Hellhammer, Jun 25, 2011
    Last edited by a moderator: Jul 28, 2014

    Moderator emeritus


    Dec 10, 2008

    I see questions about SSDs being posted everyday and they often ask the same questions. My goal is not to stop people from making new threads, absolutely not. However, I think it would be good to have one big post/thread that includes the basic information about SSDs, which can then be linked to posts asking about SSDs. The idea of this thread is that anyone can contribute to it. If you think something is missing, please PM me. You can either write it yourself which I will then add (and cite you of course) or you can ask me to investigate and write about it. I would prefer you writing it yourself because my time is limited (I have mod duties and some real work to do as well).

    SSD vs HD - Is SSD worth it?

    This gets asked a lot but there is no single answer to it. With HD, you get lots of capacity for very little $. With SSD, you pay the premium even for very little amount of storage. For the record, a 60GB SSD costs roughly the same as 1TB 2.5” or 2TB 3.5” HD at the moment. The reason why there is no one right answer is that we all have different usages. If all you need is less than 120GB for example, then 120GB SSD for ~$200-250 doesn’t sound that bad, given the huge performance increase.

    So what is the performance difference then? Enormous. Hard drives have latency of several milliseconds (ms) whereas SSDs’ latency is measured in microseconds (µs). Depending on the SSD and HD, the SSD can easily have over 100 times lower latency. The latency isn’t the only thing that separates them. SSDs sport much higher read and write speeds. Regular HDs top out at around 150MB/s but the fastest SATA 3Gb/s SSDs can provide up to 285MB/s, which is the maximum of SATA 3Gb/s. SATA 6Gb/s SSDs can offer speeds of up to 550MB/s currently, over three times faster than traditional HDs. Just to show the capability of SSDs, there are some enterprise level SSDs that deliver speeds of over 3GB/s.

    Western Digital VelociRaptor 600GB vs Intel 320 Series 160GB
    SSD vs HD - boot time

    The performance difference isn't the only advantage. Since SSDs have no moving parts, they are inaudible. HDs, especially 7200rpm ones, can be quite noisy when reading or writing data. SSDs also run cooler and in some cases use less energy (there are different results on this. Some say it increases the battery life, some say it stays the same or even degrades).

    A good SSD is also a lot more reliable. Most of us should be aware that HDs are very unreliable and some of us have experienced HD failures and even data loss. HDs have moving parts so sooner than later they will wear out, that is a fact. However, don't think your SSD is immortal though. NANDs lose their charge after about 10 years so that is about the maximum life span of an SSD. Of course, something else may fail sooner, for example the controller. There is also the wear out factor which will be covered later (finite amount of P/E cycles).

    What does SSD speed up?

    While I said the performance difference is enormous, it is still limited to certain tasks. It can’t speed your encoding times because the drive is not the bottleneck, it’s most likely the CPU. In games, it may speed up game loading times but the actual frame rate and graphics will not be improved, again because the drive is not the bottleneck.

    SSD will speed up anything that involves reading or writing of the drive. Tasks like that include but are not limited to: booting, launching apps and file transfers. People say that the OS feels more responsive with an SSD, which can be true because your slow HD was the bottleneck before. If your OS is in the SSD, then the swap file will be there too so in case you run out of RAM, the system shouldn’t feel as unresponsive as with an HD because the SSD is so fast.

    Which SSD to buy?

    I again want to start off by saying that there is no single answer to this. It all depends on your budget, needs and Mac. Here are a few things to consider:

    1. Capacity. How much capacity are you going to need? This is the number one element in determining what SSD to buy.
    2. Budget. This could be the first one too but in my opinion, it is useless to buy an SSD that cannot fulfill your needs.
    3. Mac. Different Macs have different SATA revisions and even different drive form factors. You should buy one that is the most suitable for your Mac.
    4. Usage. For general usage, it won’t matter much what SSD you get but if you are getting an SSD for serious work, then it can be crucial to get one with the best performance.

    So what SSD to buy for what Mac? Lets see:

    Any Mac with SATA 1.5Gb/s or SATA 3Gb/s (i.e. pre-2011 Macs): Intel 320 Series. Why? Because it is relatively fast, reasonably priced and probably the most reliable MLC SATA SSD on the market at the moment. Intel also offers an OS-independent firmware updater so you won’t need Windows to update its firmware.

    Macs with SATA 6Gb/s: This just got a lot harder. I have yet to see a totally trouble-free SATA 6Gb/s SSD. No matter what SSD you pick, there seems to be some issues. All 6Gb/s SandForce based SSDs seem to be having a share of issues which look like firmware related. Intel 510 Series isn’t perfect either. There seem to be random slow downs and long boot times with that SSD. Crucial m4/Micron C400 uses the same controller as Intel 510 Series and thus shares the same issues. In fact, Crucial even pulled MacBook Pro from supported machines list.

    It’s important to note that there are plenty of users with no issues. For example AnandTech tried to recreate the issue in their 2011 MBP review but they were not able to do it. It’s also worth it to note that at least 17” MBPs are experiencing some SATA issues. Moreover, 2011 MBPs are supposed to have two SATA III ports, but some of the earlier versions only have one SATA III port. MBPs built in late May and June most likely have two SATA III ports. Some users have stated that they have two SATA III ports even though they bought their Macs at an earlier time.

    Performance degradation and TRIM

    TRIM is a command that allows the operating system to inform the SSD controller which files are no longer in use. In other words, when you delete something from the ssd, the operating system does not erase the actual data from the drive, the OS will just mark that space as free space and overwrite the data when needed.

    However, the issue with mainstream SSDs with MLC NAND is that only blocks can be erased, individual pages cannot be. To make this simpler, think page as a file and block as a folder. So, if you want to delete one file (page) inside a folder (block), the whole whole folder needs to be erased and rewritten to get rid of that file. The issue raises when you don't have TRIM because the SSD controller still thinks that the file is in use. When the OS decides to overwrite that file, you first need to read the whole block to the cache (usually DRAM) and then you can rewrite the folder (block). The difference is that if you had an empty block, only the write action would have to be done. Now the SSD needs to read the while block first and then write. For the end-user, that appears as performance degradation. It looks like your write speeds have gone and they can easily degrade by 50%.

    With TRIM, the OS can inform when a file has been deleted and the SSD controller can do this action in the background. You won't have useless files floating around, thus write speeds will remain great.

    Windows 7 supports TRIM on all SSDs. As of Mac OS X Snow Leopard 10.6.6, TRIM is enabled on 2011 Macs with SSDs. OS X Lion is to add TRIM support for all Apple SSDs. As of DP4, third party SSDs are not supported. This may change in the future though. For third party SSDs, there is TRIM Enabler, but it is known to cause problems for some SSDs see the forum thread for more info).

    AnandTech's article covers this through with a great example. If you are interested in this whole performance degradation issue, read that, it will open your eyes a lot. In my opinion, the performance degradation issue is overhyped. Most of today's SSDs have very effective garbage collection which helps if your OS does not support TRIM. A good SSD will experience little to no degradation, even without TRIM.

    NOTE: This is still in progress and you can help me building it by PMing me. I plan on updating this when new information is released too.

    To do list:
    • Performance, different usages etc. Will get this done ASAP
    • Performance degradation and TRIM - What it is, how it works, is it necessary, support in OS X etc
    • List of SSDs with specifications and their current compatibility with Macs and OS X (maybe a fancy table?)
    • Alternative methods (OptiBay, external SSD etc)
    • Wear out (finite amount of P/E cycles)
  2. macrumors Core


    Jul 24, 2006
    The Ivory Tower (I'm not coming down)
  3. macrumors member

    May 22, 2011
    Thanks! I already ordered mine but this is a great idea! The opitbay options would be helpful too.
  4. thread starter Moderator emeritus


    Dec 10, 2008
    Guides section is pretty much dead at the moment. MBP forum is where most of the SSD questions are asked, thus I think this is the best place for it.
  5. macrumors 68030

    Dark Void

    Jun 1, 2011
    Cimmerian End
    nice post and good points.

    i think you have a lot of good info covered, and the to do list seems on point.
  6. macrumors 65816


    Apr 24, 2011
    Nice job, this could help a lot of people out!
  7. macrumors 6502a


    Nov 11, 2007
    How about adding a list of the contenders with features and price points? Eventually you might add user feedback.
  8. macrumors 68000


    Sep 9, 2009
    Where the fresh snow don't go.
  9. macrumors 65816


    Apr 30, 2011
    so 4 a new macbook pro wut shuld i get??!?

    Just kidding :D
  10. MJL
    macrumors 6502a

    Jun 25, 2011
    I see a number of discussions on this subject but seldom see mentioned that a SSD has no noise level (a HDD is often louder than the fan) which is very noticeable working during the night. If implemented properly a SSD will have a life expectancy far above that of a HDD. Data retention of a SSD is also higher than that of a HDD (10 years in most cases). A SSD is not affected by magnetic fields (some medical uses e.g. in an area with MRI.)

    The other item seldom mentioned is the effect of over provisioning (e.g. see Intel's website) where when one assigns only 48 Gb of a 80 Gb X25-M and the life expectancy goes up by a factor 5 and performance goes also up by a factor 4.6 (if I remember correctly). This means that althought the cost per Gb goes up the total cost of ownership goes down for the life of the SSD.

    On another note: It is near impossible to retrieve deleted data from a SSD by forensic specialists. (There are legitimate uses like financial markets trading systems or where one does not want intelectual property to fall in someone else's hands). To some this is a great plus.
  11. thread starter Moderator emeritus


    Dec 10, 2008
    I have added some more info regarding 2011 Macs and their SATA problems as well as a summary of performance degradation and TRIM. Thanks to miamirulz29 for help!

    MJL, thanks for those. I will add them ASAP :)
  12. macrumors 6502

    May 22, 2010
  13. macrumors 68040


    Dec 5, 2009
    You might want to add a few things in the "is it worth it" section.
    Bigger difference are random reads and writes, which usually occur during App launching, normal OS operating and stuff (less so in games and media which is mostly sequential. An average HDD with 70MB/s read speed usually only shows something like 0,5MB/s random read speed. Compare that to a decent SSD with about 50+ MB/s and there is another times 100 improvement. Much more impressive than the difference in write speed and also the cause for many of its praised speed increases.

    Secondly they make no noise and with MBPs and even though the fans never stop (as they do in many Windows notebooks) those fans at 2000rpm are still much more quiet than a 5400rpm HDD and the noise is also deeper and less annoying.
    A MBP isn't loud with an HDD but there is a big difference between not loud and almost inaudible at night in silent environments.

    Yes and add some info about optibay as mentioned.
    Some mod should make it sticky as soon as everything is it.
  14. thread starter Moderator emeritus


    Dec 10, 2008
    Still on my to-do list. If people just didn't break the rules that much ;)

    I added this in my previous edit.

    Working on it as we speak.

    Well, I am a mod ;) However, our sticky policy is pretty strict and it's rare that we add stickies. I can ask though.
  15. macrumors newbie

    May 19, 2011
    Wirelessly posted (Mozilla/5.0 (iPhone; U; CPU iPhone OS 4_3_3 like Mac OS X; en-us) AppleWebKit/533.17.9 (KHTML, like Gecko) Version/5.0.2 Mobile/8J2 Safari/6533.18.5)

    It would be great if there was a little about setting up the SSD. When I first came to this forum there was alot of different information on how to setup your SSD in regards to settings, such as: "Unticking" the go to sleep for the drive option when you have an SSD installed.
  16. macrumors Core


    Jan 23, 2005
  17. macrumors member

    Mar 19, 2011
    Is there any real world major difference in performance between SATA 2(3Gbps) and SATA 3(6gbps)???
  18. macrumors 65816


    Apr 30, 2011
    Only if you're copying between two SATA 3 drives on SATA 3 controllers. Otherwise, it's negligible.
  19. macrumors 6502

    Oct 14, 2008
    nice work, very informative. perhaps this should be made a sticky or something
  20. macrumors 6502a

    Oct 27, 2008
    personally i'm leaning towards the apple-branded 256gb ssd option. the apple 128gb option seems to be a far more popular recommendation for people wanting an inexpensive way to get into ssds, but i know there's no way i'd be able to constrain myself to that amount of space.

    seems like most people going for higher capacity just opt for a 3rd party drive, but for me, it feels like the native trim support and slightly cheaper price would be the best compromise for now. i figure i'll consider a proper SATA III upgrade in a year or two when i can hopefully get 500gb at the same price point.

    part of that justification, however, stems from the psychological feeling that an "apple-approved" drive would be sacrificing bleeding edge performance for some sense of increased reliability. but has anyone actually gone that route and can confirm or dispel that notion?
  21. macrumors 65816


    Dec 26, 2009
    Deep Space
    As for the OP's comment that third party SSD's are currently not TRIM supported:

    Sounds like it's not a good idea to buy third party SSDs?
  22. macrumors newbie

    Jun 5, 2011
    As also stated, there are ways to get trim to run on non-native drives
  23. Alexjones, Jul 2, 2011
    Last edited: Jul 2, 2011

    macrumors 6502

    May 28, 2010
    I want to buy a second MBP with a SSD. The one i have now has a 7200 RPM HD and works like a gem. Should i go with the SSD? Will i notice a difference?
  24. macrumors Core


    Jan 23, 2005
    You will notice a big difference in initial boot time and the startup time of apps, but once the system is running and you have all your apps started there is not much of a difference. I will qualify that by saying if your normal usage it to import say large video/image files into app, then that will be much faster.
  25. macrumors 65816


    Dec 26, 2009
    Deep Space
    So for video editing an SSD would be a great advantage...
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