New to SSDs, info please

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LordWolf

LordWolf

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Jan 29, 2011
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I've done a little bit of reading and know that SSD's will tend to degrade or encounter issues based on the number of writes made or something along those lines. I know it's some outrageously high number and it's a bit more to it than just that but it has me wondering, what is the minimal life span of an SSD where there is an unusually high number of writes made to it? I'm not expecting to put a drive under that sort of usage, but I would rather assume over usage to be "better safe than sorry."

Also, are there any brands and/or particular models that are considered better than others (and likewise, worse than others, that I should avoid)? I'm looking to make a purchase from NewEgg, with a storage of 120g to 250g, depending on price. To clarify what I mean, I'm looking for the least expensive (but best quality) and will likely be 120 to 128, but if there happens to be one that is of larger capacity for a good price then I might grab that instead.

So in short, what do I need to know when looking for SSD's? How sturdy/durable/reliable are they? What brands should I look at and which should I avoid like the plague? As with above, what is the minimal life expectancy (when under unusually high usage)?
 
Solution
nukemaster
I will try to clear up some of your questions.

Why do SSDs degrade? Its a multi part answer.

Going to simplify as much as I can.

SSD Flash has many cells and that is the place the data is stored

SSD cells on most consumer SSD's(MLC) write 2 bits of data to a cell. Both bits HAVE to be together at the same time. If you write half the cell, no harm is done, but on the next write to the cell, the data has to be erased and then written again with the new data added.

This is part of the issue faced with many early SSDs.

An SSD as it fills up has less and less "Free" or empty cells to write data to. so you would guess if you had to go around condensing the data from all the half full cells to make full cells and free up new cells for...
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Thanks, but that doesn't appear to answer what I'm wanting to know. Sure, it gives some rankings and benchmarks but that's on a technical scale and most of it is above my understanding at this point. At the same time, I didn't see a reference to life expectancy (I skimmed it so it might be there and I just missed it), nor which brands/models have been known to thus-far fail more often than others and which brands/models have been unexpectedly great or exceeding expectations. When looking at an SSD's specs, what should I look at? What is important or unimportant?

Hoping for a bit of a 'cheat sheet' for determining what is a good drive based on advertised specs, then from that list, eliminating those that people have had problems with. To put it simply, I would ask for what I specifically need to know, if I knew what it was that I specifically needed to ask for. I just want to make sure that when I go to make a purchase, that it won't be one that I regret or look back on and say, "I wish I had known about...."

 
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M4, Mushkin Enhanced Chronos Deluxe, Samsung 830, pretty much anything from Intel all receive good reviews for reliablilty on these forums. As far as statistical evidence, I got nothin...

How long it lasts depends on your usage habits so it's hard to say. Supposedly the individual blocks fail in a readable state so nothing is lost, just over time your writable space shrinks.

My theory is that with the rate capacity is increasing and prices are dropping, by the time mine wears out (3 years? 5 years?) it won't be a big deal to get a reasonably priced, newer, faster, bigger model.
 
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I will try to clear up some of your questions.

Why do SSDs degrade? Its a multi part answer.

Going to simplify as much as I can.

SSD Flash has many cells and that is the place the data is stored

SSD cells on most consumer SSD's(MLC) write 2 bits of data to a cell. Both bits HAVE to be together at the same time. If you write half the cell, no harm is done, but on the next write to the cell, the data has to be erased and then written again with the new data added.

This is part of the issue faced with many early SSDs.

An SSD as it fills up has less and less "Free" or empty cells to write data to. so you would guess if you had to go around condensing the data from all the half full cells to make full cells and free up new cells for more writing this would hurt performance. It does.

Now with modern drives and operating systems, this is not as much of an issue. TRIM helps this as does background garbage collection. On many drives when idle(BGC), the drive can make sure all the cells are full and free up extra cells to write to in the future.

To make this more complex the drive it self has to know how many times each cell has been written. This allows it to spread new writes over cells with the least writes(it is technically the erase it would track irc) first. With this ware leveling, the drive will ensure ALL the cells ware out at the same time. This greatly increases the life of the drive. If you wrote over the same cell over and over again, you would run out of the (newer flash)3000-10000(older flash) cycles in no time. Strangely enough, newer flash has less write cycles, but this may be more on paper.

A modern SSD will still has you a long time.

As for brands, Intel is generally considered best. The offer a longer warranty to back that statement as well.

It best best to check the reviews, but always not that if you sell 10000 drives and your competition sells 100 drives, you may end up with more bad reviews in the 10000 drives. OCZ seems to have very mixed reviews, but since I have not tried, I can not comment for sure on it.

Other info you may find useful.

You may wonder why they have 60/64 and 120/128gig drives. Some drives have what is called over provisioning. When setup right, this can help the drive not run out of free cells as easy and can also even be used to remap any failed cells. Both 60 and 64 gig drives have 64 gigs of flash, the 60 gig just has that extra 4 gigs over provisioned. Some drives like OCZ's cache drive even have half the flash over provisioned(I would be those drives never slow down :) ).

Some controllers for the drives will compress data(sandforce) if it can.
These drives will have VERY high speeds if the data is compressible and slower(not bad slow) with non compressible data.

Other drives that do not rely on compression like the crucial M4 listed above does provide more constant results. It all depends on your workloads.

Cheaper drives tend to have async flash. It is cheaper and does not perform as well under some workloads.

Next up would be sync flash.

Toggle flash is all around considered to be the BEST.

The price of the drives generally reflects the flash type used.

Toms had a review of 60gig drives. This review will also give you some good info on how different flash can perform.

http://www.tomshardware.com/reviews/ssd-60gb-benchmark-review,3137.html
 
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Solution
The simple answer to your main question is that by the time you wear down the NAND Flash in an SSD to the point of failure, it's going to be obsolete enough that you'll be glad it's dead. More than likely you won't see it happen (kinda like seeing a cmos battery die, by the time it would have happened it's usually in a landfill).

All of that said, I typically store as little personal data on an SSD as I can, disable the pagefile/tempfile on the drive, and do what I can to minimize the amount of writes that take place, but that is as much to conserve precious space as it is to minimize writes. The more free space you have the better, and the bigger the drive is, the more spare room you have for wear leveling, garbage collection, etc.

I pretty sure the following is true for sandforce SSDs, not sure about others (but my guess is that it's similar); but the NAND is overprovisioned in SSDs (so a 120GB ssd will contain say 140GB of actually NAND Flash), and the data being written to it is compressed and spread amongst the available space. The controller keeps track of how much each block of each NAND chip has been written, and evenly distributes write cycles throughout the drive as much as it can. The compression that takes place means that when you write 1GB of data, you may actually store only 500MB into actual NAND, the other 500MB that was saved is not really accessible by you (so you can't store an extra 500MB on the drive) but it gets used by the wear leveling algorithms to evenly distribute writes.
 
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Looking at reviews is definitely one thing I've been keeping in mind. After all, if a drive has over 100 reviews and a majority of those are under 4 stars, then that's a sign to avoid it (IMO). I tend to be very picky when buying something, where I look at the total of 4 & 5 stars (on NewEgg) and if that doesn't make up roughly 80% of the reviews (or if it has a low number of reviews), then I tend to keep looking. Would rather pass up on a good product that just happens to have a lower rating than to risk those bad reviews being a prediction of my future.

So if I understand what you're saying, a 120gb drive is really 128gb, but 8gb of that space has been 'stolen' to provide a longer life for the drive. Is that about right?

How do I tell which type of flash a drive is using?

From what 'J_E_D_70' said, if a drive starts to become unwritable (so to speak), would I still be able to retrieve the data already on there? What I'm thinking is, if I realize that the drive is getting close to being no longer usable, could I do a 'quick format' and then attempt to stuff if full of files/pics that I want to keep and then always be able to access it even if I can't write much more to it (if at all)?

How would I determine how long a drive should last for me? I'm not a gamer but I'm sure I tend to do slightly above-average use of a hard drive. If I were to use an SSD as my boot/system drive and if I even kept a pagefile on it, let's also say only 4gb of RAM (I have more than that, but again, would rather go based on tougher values to be safer). Also, computer almost always on. So, putting a bit of a load on the drive. Would it be only about 3 to 5 years or would it be 10 or more? Has anyone (that you know of) managed to wear out an SSD?

What about reliability as far as loading it full of data and then storing it somewhere? Is it immune to magnetism?




Just what is 'garbage collection'?


Sorry if I sound like a mega-noob or dummy on this, just want to make sure that when I make a purchase, that I won't look back on it and be like "Doh! If I had known (whatever) before, I would have bought this other one..."
 
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It is stolen in the name of reliability/redundancy(sort of like if a hard drive reallocated a sector) and for the controller to do as it sees fit with so to speak.

Garbage collection is the drives way of at idle time condensing half filled cells into less used cells my merging them. This allows the drive to have a nice pile of free cells when it needs to.

In general, when the SSD cells no longer work, the data is supposed to be accessible(at least thats what the NAND flash makers say). If it works that way in the end is anyone's guess. The flash makers list something like a 10(or some other long time) year data retention. Either way, at some point in time, the flash WOULD loose its data.

This biggest issue is that most people who have killed a SSD had it just stop detecting. Without that, recovery is not so nice.
 
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Garbage collection is basically physically deleting things that have been flagged for deletion. When you delete a file in windows, the space it uses is flagged for deletion, but it isn't always deleted because it maybe sharing part of a block with another file (blocks are 1kB or more usually), so it leaves the block in place and later, goes around and reclaims all the 'half-blocks' it has lying around into full blocks (essentially a very low level defrag), and prepares the empty blocks for being written again (by writing all bits to 1's, then a write will set 0's in place).

Regarding your concerns about losing data, as I said, I like to keep my data off my SSD (often the controller in an SSD is more likely to cause trouble than the nand).

I move my Users and ProgramData off of the SSD, so that all my personal data, save games, etc are always on an HDD, but I still get great boot times. From there, I just install basic apps and drivers to the SSD, and symlink any games I am playing to the SSD.

If my SSD wiped data right now, I would be set back about an hour, maybe two with no lost data, just a few apps.
 
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Nice that is about how i am setup for win8.

Been moving personal folders to another drive since win98 :)

On windows 7 my games are on the SSD and windows 8 links to my windows7 steam/other games data that are in term partially(just the games I use) linked to another SSD :)

Games I play get the SSD, the others get to live on the hard drive. works very well.
 
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One thing to look for is the longevity of the flash. Premium Toshibs Toggle Mode Flash for example lasts 2-3 times longer than the flash found in entry level SSD's

http://www.tweaktown.com/reviews/4328/mushkin_chronos_deluxe_120gb_solid_state_drive_review/index13.html

Other than a few really oddball entries, SF-2281 'consumer' SSDs come in three flash flavors. Starting on the low end, you have IMFT 25nm asynchronous flash, a budget flash used in the Agility 3, Force 3, Chronos (non-Deluxe model) and a few other drives that in our testing perform at around the same level as last year's SF-1200 controlled drives when filled to 50 percent capacity. A majority of drives use IMFT 25nm synchronous flash; Vertex 3, Force GT, S511 and so on.

Synchronous flash, also called ONFi 2.x is really the first step for enthusiasts, especially now that prices have really dropped. The final flash type used is 3Xnm Toggle Mode flash from Toshiba, a form of ONFi 2.x without the JEDEC classification. 25nm IMFT is rated for around 5K P/E cycles and 3Xnm Toshiba Toggle Mode flash is rated for around twice as many. Even though we are talking about writing a lot of data for a very long time, the 3Xnm flash will still last even longer.

At this time there are very few consumer SSDs that use Toshiba Toggle Flash; you can count those available in the US on one hand - Vertex 3 Max IOPS Edition, Patriot WildFire, OWC Mercury Extreme Pro 6G (240GB capacity size only) and what we looked at today, the Mushkin Enhanced Chronos Deluxe. That said, the Chronos Deluxe is in a very limited class of products right from the gate.
Click to expand...
 
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Okay now I'm wondering, if I get a 128gb SSD, would it spread out the usage so that the amount of available space would start to decrease in order to remain useable? To ask it in a different way (make sure we're both on the same page), let's say I get a 120gb SSD and allocate 100gb for the system and 12gb for a page file. That leaves 8gb unallocated. Over time, if that 12gb partition starts to "wear out", would it start 'stealing' from the unused 8gb to keep the 12gb area useable?



So are you saying that when it's unwritable, then it simply becomes undetectable as well?



I take it that it's recommended to turn off defrag for SSD partitions. So when a file is deleted, is it that it 'completes' the deletion by combining multiple half blocks, so when it writes to some of the blocks (to clear them) it's not doing an extra write, just changing what the write is? (ie, if it's going to write to it to clear half the block, it may as well clear the entire block after it moves the other half to another block that was going to be written to anyways)


Okay I know it's possible to do this and I've done it before but how do you account for the different unique user ID values when reinstalling the system? Like if I were to do a fresh install right now, the (SSID?) would be different even with the same account name. Do you just go in and change the owner ID or do you somehow recover your user account in the new install? A step-by-step for this would be nice. I'm into retaining data as best as possible and am thinking about having two partitions mirror each other so if one drive goes bad, the data will still be available.



Please dummify for me. What is a keyword that I should look for to either avoid (don't buy it) or prefer?

Also, have SSD's progressed enough that a casual user like myself should start using them? Don't get me wrong, I'm actually rather good when it comes to computers, just not so engrossed that I know all the in's-and-out's of them. Used to be somewhat engrossed, but over time it's a ton of new information to keep up with so I stick with knowing how to put together computers but not trying to know every little detail about every component. So I guess this question would be more of, are SSD's still in a stage that is for enthusiasts or have they reached the point of being more mainstream? Much like there was the HDDVD/BluRay war, those who were heavily into it were the ones buying them but now it's just about the same as buying DVD's, where not only prices are down but most of the 'glitches and kinks' are worked out. I hope where I'm coming from is understood on that question.
 
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SSD's do not use sections of the drive like a hard drive(So the first partition at the outer edge and so on). So if you partition it that way, it will still distribute data to the least used sections of the drive(no matter what partition you are using). Windows will see the data as in the partitioned space, but at the drive level, the controller will be the only one that knows the data location.

It should not. The flash makers say the flash can go read only, but I do not think any normal users has ever burned past all the program erase cycles of a SSD. I mean on another forum some users have been stress testing SSD's and wrote over 700000 gigs(700+ TiB) to a 64 gig M4 drive. While the drive is only spec'd at 172000(172TiB)

You want to see some endurance testing? Some drives did not make it, but was that a defect? maybe.
http://www.xtremesystems.org/forums/showthread.php?271063-SSD-Write-Endurance-25nm-Vs-34nm


I do just replace the owner, I have not had to reinstall windows that many times. Since i have the "Everybody" group able to read(not write), I can always slap one of my drives in any computer and copy needed data. For my games, while they do have a different owner(Windows7 login VS Windows8), they all seem to work just fine this way(Some games/programs will still use appdata/programdata and other folder so not ALL the files stay on the second, third, ect drive).

I have always used windows built in options for this, but with software like Junction Link Magic(an Easy way to do something windows will let you do anyway from the command line), I admit I would be interested to see if a junction would work better then windows own move folder since some games(Unreal3 based) did not save data right with a custom Documents folder location(The work around was just to add "-nohomedir" to the shortcut, but still.).

You can check out this software, but do not mess with things you are not sure of, you can break the system good with it. Just install a game, copy its folder it to another drive then empty its folder(on the first drive), create the junction from the now empty game folder to the other drives new game folder, and then the game never knows it moved.

If you look at this image, you will get an idea of what happens.

my steam looks to be on c: (win8) but it is fact on g: (win7). Now some games like Just Cause 2 happen to be on f: (games). So while windows 7 and 8 can both access this game, they both share one copy on f:, but each version of windows(and more important, steam) sees it on its own drive. All steam data Windows 8 uses(a junction to make steam appear to be on c:) is from the windows 7 drive. The windows 7 drive had some junctions to f: for some games. So any changes made on either system are happening of f: its kind of cool to add a folder or file to any of those 3 windows and see it happen on all

Ohh an Just Cause 2 loads so fast off a HDD, the SSD does not help that game. Others are helped.
http://img20.imageshack.us/img20/1989/junction.png <-image not in forum because its too big.

http://www.rekenwonder.com/linkmagic.htm


I think they have. I waited out the BD/HD-DVD thing too.

I still keep my personal files(It does not require speed to edit text/images, listen to music or watch movies.) on hard drives(5900 rpm slower drives too) and a second and third(can never to too safe) copy on externals. Why? Hard drives are proven technology in my mind and offer good long term storage(Not to mention HUGE space for the price).
 
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Check out this guide for some tips on tweaks that you should make to an SSD.
http://thessdreview.com/ssd-guides/optimization-guides/the-ssd-optimization-guide-2/

Seems like it maybe worth explaining how a write is performed on a piece of uninitialized flash. So flash cannot set 1's and 0's like a typical Magnetic drive; in order to write, the flash must be erased by writing all the bits in a page (usually 1k or so I think) to 1's, it does this by applying a high voltage to the page and essentially filling all the tiny electron traps used to store data, this is the pages erased state, and it is always performed on a full page (not individual bytes) and is the only way to actually put 1's into flash. From there, the write operation opens some of the electron traps, releasing electrons to bring individual bits back to a 0 state, leaving behind 1's where needed to create useful data.

It's a bit like an etch-a-sketch, in that you can't set a bit back to 1 once it's been 0'd, other than by starting over entirely (per page).



This is the method I prefer to use for moving my Users directory: http://lifehacker.com/5467758/move-the-users-directory-in-windows-7

It is also effective for moving the ProgramData folder (where most programs store their settings) which can also get quite large. It ensures that anything that attempts to write to C:\Users is redirected to your HDD; the only issue I've had with this method is that the Windows Experience Index refuses to calculate (not sure that this caused it, but seems likely), which is pretty minor. If you are also concerned about your HDD a raid mirror array would be the best way to go to ensure data integrity, otherwise just doing periodic backups is enough.
 
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Very nice. and FAR better(for a single OS) then what I currently do(I just take Docs/Desktop ect).
 
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I started out doing my transfers that way, but it got so annoying to redo it over and over again when I reformatted that I had to go in search of a better method. I've been running that way for about a year now on my PC and my Wife's, and set up a PC for a friend that way. It's brain-dead simple once you get it right. It's worth adding that I typically rearrange my drive lettering in the recovery console using diskpart before I start making links, I don't think it's necessary but it's in my ritual now.
 
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Question though. What if you already have your Users folder on the HDD and want to attach it to a new/fresh install of Win7? Would you rename the old 'Users' folder, follow the instructions and then rename the folder again? What about updating the ownership of the folders?

Just wanting to keep it fool-proof. I'm sure I'd be able to figure it out but if someone else already has the answer, why not ask and learn that way, right?
 
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You can't reuse the Users folder. There are some system files in there that, from what I've seen, seem to be specific to a particular install. I just rename to oldUsers and oldProgramData, then follow the instructions. Once the computer is up and running, just manually copy the data over from documents, desktop, music, etc. Typicaly, I'll just pick bits out of the oldProgramData folder for applications I care about (such as firefox), not take the whole thing, and leave the old folder for a few weeks to make sure I didn't miss anything.

Be advised though that the /mir option in the robocopy indicates to mirror folders, if you do this and aim it at an existing folder (for the destination) you will delete the folders contents. I don't know if the /mir is important to the process or not, but I almost lost some data once with that bit (found it hiding somewhere later) :)
 
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So then, would the idea be to take ownership of the folders/files (kind of a given) and do a mass copy but choosing to not overwrite existing files, or could that cause problems? Or would the idea be to only copy over a few specific items, like the pictures folder if that was being used?
 
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Not sure how that would work out. I typically go into the individual folders under the main user profile (so desktop, documents, video, etc), select all, copy, and paste to the corresponding new user folder.

As long as you have the old copy, you can thrash a few windows installs trying different methods. It only takes about 15 minutes (if that) to do it reformat and install on an SSD, just do the dangerous stuff first.
 
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MS is on the right track by doing a Users folder. Now if only they'd make it so there is only ever one folder that truly needs to be backed up, with other folders being optional. As it is, to reinstall FireFox without losing stuff, that's in a Roaming folder, with Pictures in a different location, etc.



Guess I'll just have to test it out. Of course, I'd make sure to use a backup copy of the data so if anything bombs, I can just make another copy and try again.


Don't suppose I could get your viewpoint on this topic?
http://www.tomshardware.com/forum/286755-32-really-quick-question-svp200s3-120g

Getting down to it, do you believe it would be a good purchase?
 
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I most commonly see Crucial M4's, Samsungs , and Intel (if you want to spend extra) being recommended around here.

The majority of the other manufacturers use the Sandforce controller, and so are essentially the same (with minor variations in quality of parts), Kingston isn't a bad brand from what I've seen, but they aren't a stand-out brand because they are just another Sandforce drive.

I personally own 2 OCZ vertexes (a Vertex2 50GB and a Vertex3 60GB), with moderate results; one failed, sent it back, they screwed up the shipping it back part, and over-nighted me a vertex3 to replace the vertex2 60GB I sent (once I got around to calling them). Not a glowing review by any means, but I was happy with the overall response, and would buy from them again.

Personally, I would go for whatever gives you the best $/GB at the size you want, performance is such a vast improvement over HDD that it doesn't make much difference between drives, as long as the quality (newegg and amazon reviews) aren't too far off from what is recommended above; in the end, the perception of quality on your end is going to be mostly based on luck (which is true for any hardware), you are just trying to work the best odds you can.
 
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