What do i need to knowabout SSDs?

[wrenaudrey]

I've never had an SSD before and im thinking of buying one. What are the essential things and tricks that i need to know?

Is it true that there is only a certain amount of reads and writes it can do before it breaks?
Apart from the cost per GB, why isn't SSDs used 'like' a normal spindle/spinning hard disk?

Thanks in advanced

 

[CaedenV]

They are AWESOME, but not as awesome as they claim on the package.

While even basic SSDs can hit 300+MBps, and really good SSDs can max out the SATA3 interface at ~400MBps, nearly all of them can only hit those speeds with compressible data. With uncompressible data even the best of drives tend to only be ~150-200MBps. These speeds are for sequential reads and writes, and (with the exception of compressible data) are not much better than modern mechanical drives.
While the throughput is good, that is not where the performance gains are really made. The real improvement is in seek time between files which greatly improves program loads, indexes, and nonsequential read/writes. Mechanical HDDs have between 8-20ms time to seek between files, while even slow SSDs have a seek time of .3ms. This is where you go from ~1 minute load times for Windows down to ~10-20 seconds. Or large programs like Adobe Premiere or most video games move from 45 sec down to ~4 sec. Most other small programs like word load instantly.

Video editing, and other bulk storage uses are still plenty fast on modern mechanical storage solutions, especially when using RAID for redundancy and a little speed boost.
Because of this most people have an SSD for their programs and OS, and then traditional storage in RAID1 or 5 for important and bulk files (music, documents, video, etc.) because there is no real advantage to playing them back at 300MBps or mere realtime of 1-20MBps.

For longevity you are right, there are only so many writes (not so much reads) that you can do before the drive breaks down. Modern load leveling helps wear down the drive evenly so that it lasts as long as possible, and most current models should last just as long (if not longer) than a traditional HDD for normal use (installing and using programs). If you are doing things with a lot of writes (like editing or other production work) then you will want a better quality SSD (like one of the ones with a 5 year warranty), or to limit that production work to traditional HDDs.

$/GB is the only reason you would not use an SSD like a traditional HDD. 2TB HDDs are only $120 (and were only $80 last fall). It would take ~$2000 to purchase 2TB worth of SSDs, and much more than that for quality drives. But as I said before, because there is no practical improvement in playing back files from an SSD vs HDD then you would just be paying out money for nothing.

There are tons of great articles about SSD optimization, so just poke around to find what is best for your uses.

 

[kajabla]

^Excellent explanation.
The biggest, most notable benefits of SSDs come in loading times, both for the OS and for applications. When you launch an application off your mechanical hard drive, it can only start up as fast as its data can get from the HDD to your RAM, and this speed is limited by the HDD's read speed. An SSD reduces this bottleneck, though it does not eliminate it completely. This means that Windows, for instance, will often load 30 seconds to a minute faster with an SSD than with an HDD, and the long hang time after hitting the desktop (I couldn't do anything on my old computer for a solid minute and a half after startup) is virtually eliminated. Programs with noticeable load times, like games and Photoshop, will launch much more quickly, and level loading times will be reduced, often by 50% or more.

Yes, $/gb is the only reason SSDs are not used like HDDs.

 

[wrenaudrey]

For longevity you are right, there are only so many writes (not so much reads) that you can do before the drive breaks down.

What did you clearly mean by this- Are the amount of writes on a SSD (in say ~10years of use) similar to a HDD (in say ~10years of use) or is it substantially really low?

 

[CaedenV]

Well, if you have a daily driver HDD then 10 years is pretty extraordinary, most HDDs that are used consistently die in 5-7 years, and that is roughly how long an SSD will last. Some more, some less, and if you are really working the drive (like using it for rendering or a server) then much less.

Also a thing of note for SSDs is that they need power to retain information. If you unplug the power from an SSD then you will begin to have data corruption after a month or two. More than enough time for most uses, but do not expect it to be like a HDD where you can shelf it for a few years and still be able to get information from it.

Longevity was a concern for first and 2nd generation drives, but the current crop is pretty solid all the way from the low end OCZ and Mushkin drives, to the high end M4 and Intel drives. They all serve different purposes, and have different things that they excel at, but they are all much better/faster than HDDs.

One last note: the same rules apply to SSDs as they do for HDDs on space usage. Never use more than 80% of your drive. Windows needs that 20% on a HDD for defragmenting, caching, and generally for it's own piece of mind so that it does not start freaking out about where to put things. On SSDs you need that extra space for caching, garbage collection, and load leveling. The drive will still work if full, but just not quite as fast, and it may wear out prematurely. So always aim for the next size up from what you think you need just to be safe.

 

[CaedenV]

What did you clearly mean by this- Are the amount of writes on a SSD (in say ~10years of use) similar to a HDD (in say ~10years of use) or is it substantially really low?

Short answer, and be warned this is just a best guess, SSDs should last as long or a little longer than a HDD of equivilant grade.

This means entry level drives should last 3-5 years. Enthusiast level drives should last 4-6 years. Enterprise level drives should last 5-8 years.

Again, this depends on your exact usage, but as a system drive for your average daily user I think this should be a close ball-park short of catostrophic failure such as a lightning strike, or some other fluke issue.

Personally I do not put any important information on my system drive, and i fully expect SSDs to drop in price, and increase in performance dramatically over the next 2-3 years, so i bought a large but cheap OCZ Agility 3 drive with the expectation that I will be replacing it in 2-3 years anyways just through regular upgrades and replacements. If you are a longer term builder it may be worth the money to invest in a more expensive drive, just because it will last a little longer.

 

[RetiredChief]

Two types of SSDs
SLC (single layer Cell). Each cell can be writen to about 100,000 times.. EXpensive!!!
MLC (multilayered Cell). Each cell can be writen to about 10,000 Times. dies faster, but much cheaper. MLC are what you typically see.

So how long. Multiply 10,000 time size 120 gigs divide by number of writes per day/365 days = Years.
Say you wrote 10 gigs a day to a 120 gig drive.
(10 to the 4th) x (120 x 10 to the 9) / (365 days x 10 to the 10th) = 128 years
Probably screwed up a decimal place but and since wear leveling is not perfect so at 10 gigs per day should last as long as any HDD.

 

[wrenaudrey]

...i bought a large but cheap OCZ Agility 3 drive ...

Thank you again for your well explained and accurate answers.
But on last thing to ask, you mentioned you bought the OCZ Agility 3, is this product good? is the whole company good? how does OCZ compare to like Corsair and Intel SSD?

I have taken a few minutes to filter out OCZ, SATA-III, 120GB-128GB:
http://www.ebuyer.com/search?page=1&sort=popularity&limit=10&store=33&cat=385&filtermfr=416&filterea19=115+-+128&filterca5320=SATA-III

What are the differences between what you see in the link above?-Agility, Vertex 3, Vertex 4, Petrol, Octane, Synapse?

And lastly, what is the best bang for your buck SSD?

 

[RetiredChief]

As I indicated I have a pair of 128 gig Agility III, But even I make mistakes - LOL

The Agility III performs the same in a Sata II port as it does in a sata III port which indicates that it is not taking advantage of the Higher bandwith. ATTO Bench mark will show higher sequencial performance on a sata III port - BUT that is using Data that is readily compressable. A review brought this to my attention and I checked mine, Using AS SSD, the performance was about the same for sata II and SATA III. The next thing is take a look at the 1/2 egg ratings for the Agility III vs the M4, or the Samsung 830, Big difference.
They have pretty much fixed the mired firmware problems with the drive, only took them about 8 Monthes of blaming the user.
I only recommend the Agility III when $$$ is the overriding consideration.
I took a Solemn oath never to by OCZ, The company does NOT have a good rep.
Off the soap opera.

 

[wrenaudrey]

So RetiredChief, you're saying that OCZ's Agility series is bad? So what's better to get?

 

[RetiredChief]

I can not say it's "BAD", it's just not my choice and if that is all the $$$ wil by then go for it. You just need to know you are getting a SATA II SSD with a SATA III wrapper, At least in my oppinion .

What is the most recommended are The Curcial M4s, the Samsung 830s and the Intel 510/520s. (510 uses the marvel controller simular to M4s while the newer 520 uses a SF22xx, simular to OCV vertex III.
I agree with this recommendation. As to which one of teh three, which ever is cheaper. All three enjoy good user ratings, Very slight difference in real live usage.

One comment - the VAST majority that have upgraded to an SSD will flat out say, they will not go back to a mechanical HHD for OS + Programs.

 

[CaedenV]

OCZ Agility 3 is not bad, it is just 'low end' which means it is not as fast as other drives, and will likely wear out faster than other drives. If I thought it was a bad product then I would not have purchased it in the first place, but to say that it is the 'best' would be overselling their product.

Here is what I purchased http://www.newegg.com/Product/Product.aspx?Item=N82E16820227727
I got it at my local Microcenter a month or so ago for the price that it is on newegg now. It is a cheap 'value' drive, which basically means that it is not as fast as the competition (still damned fast though), and that it will likely wear out sooner than the competition because it is made from cheaper parts. The product still works, and I fully expect to get at least 3 years or more out of it, but I would be surprised to get 5 or more years of use out of it.

As Chief said, Crucial M4, Samsung 830, and Intel drives are the better options for performance and/or longevity, but you also pay for it. In the case of a 240GB drive the Intel drive costs over $100 more than mine. If I stored important information on the drive, or if I needed absolute performance from it then it would be worth purchasing. But as it is only a system drive, with all of my important files on a little RAID array, there was no pressing reason for me to spend that extra money on it. When the drive fails in 3-5 years I expect I can get a drive twice as fast, and twice as large, for ~1/2 the money, and at that point I will get a real 'performance' drive because SSD technology will have matured by then.

In short: If buying short term, then just go cheap. If buying long term, or as a single drive system, then spend the extra money and get one of the better drives.

 

[CaedenV]

What are the differences between what you see in the link above?-Agility, Vertex 3, Vertex 4, Petrol, Octane, Synapse?

And lastly, what is the best bang for your buck SSD?

The old lineup (Sand Force):
Solid 3: Entry level Sand Force SSD (picked up a small one for my wife's PC last August, works like a champ so far), this product has been discontinued and merged into the Agility line
Agility 3: Use to be the Mid-level SSD, but currently it is the entry level Sand Force SSD, and what I picked up for my PC
Vertex 3: High end SSD based on Sand Force
Vertex 3 Plus: Extreme performance Sand Force, no firmware caps (it runs as fast as the flash can run), tends to have the best parts in it

The new lineup (Indilinx):
Petrol: Entry level Indilinx controller SSD. Avoid as this is a first gen product. It works, but as with any first gen product it has a few stability issues
Octane: Moderate to High performance Indilinx SSD. I have not heard the stability complaints that Petrol had on this, so it should be OK
Vertex 4: High end and Enthusiast grade Indilinx SSD

Synapse Cache is not intended to be used as a stand alone drive (though I suppose it could be used as one). Cache drives are meant to be paired with a HDD so that you have the 'reliability' and space of a HDD, but then the SSD is used to cache often used information so that you get a dramatic speed boost from those operations. As these drives are written to a lot more than a regular SSD they tend to have much better quality chips in them so that they last longer.


Sand Force vs Marvel/Indilinx:
Marvel is the generally 'better' product in that it is more stable, has better garbage collection, and a few other features. Sand Force is (or at least was) the cheap alternative, which sacrificed a little bit of stability for faster write speeds. These days though they are rough equivilant to each other, and even Intel is using Sand Force, while OCZ (typically the 'value' priced drive maker) is moving over to Indilinx which is based on Marvel. So do not think that one is clearly a better or worse platform than the other. Marvel has more consistent performance, faster reads and slower write speeds. Sand Force is a little more open for development from the company using it, so there is more variety in sandforce based products, and it reads and writes at close to the same speeds, but that speed is not quite as consistent.


To answer your question: Agility 3 or Octane are going to be the best !/$ on the OCZ lineup, with Octane being a better quality product, but as a younger product it may be more prone to problems and/or critical firmware updates (and every time you update firmware it is like reformating your drive, so it can be a pain). The Vertex line is clearly better, but you also pay a bit more for it, and the competition (Intel, and Samsung) have better products for a similar price.

 

[CaedenV]

Two types of SSDs
So how long. Multiply 10,000 time size 120 gigs divide by number of writes per day/365 days = Years.
Say you wrote 10 gigs a day to a 120 gig drive.
(10 to the 4th) x (120 x 10 to the 9) / (365 days x 10 to the 10th) = 128 years
Probably screwed up a decimal place but and since wear leveling is not perfect so at 10 gigs per day should last as long as any HDD.

Due to the nature of the memory used in SSDs the drive has to be rewritten periodicly, and load leveling creates a bunch of extra writes as well

In my case I have a 240GB drive, and I am using ~120GB of that so far. Lets be harsh and say that all data on the drive is rewritten every month just for storage maintenance, which comes to 120GB per month, or 1.44TB per year, just to store information. Windows uses ~2GB per day in registry changes and other maintenance (Virtual memory turned off as I have 16GB of ram, if virtual memory was on it would be an extra 16GB per power cycle, and if I tapped into virtual memory then it would be exponentially higher), and then I stream a ton of HD movies and large files so I am going to say that I average 18GB per day (likely a little high), for a nice even 20GB per day in total writes for use, or 7.3TB of data per year (*sigh*... my ISP must hate me). All told we are talking 8.74TB per year of wear, on a drive that has (240GB*10K write cycles) 2400TB of longevity.
2400TB longevity/8.74TB per year of use=274 years of use lol. Something tells me it will die long before that


But, to a point: Lets assume that I purchased a 120GB drive, which would have a longevity of 1200TB. Because my drive would be full all the time (I have ~100GB use in just OS and programs) the load leveling and GC would have to work much harder which is going to hammer the drive. When a drive is hammered it can be rewriting the whole drive every day or two (or even more often), which on 100GB means ~18TB per year to maintain data. Add to that my 20GB per day workload from the previous scenario and we have 25.55TB of use per year.
1200TB longevity/25.55TB use per year= 40 years of use


While the math is correct, the 10000 cycles on the flash is not because some of that memory will die prematurely creating an exponential load for the remaining memory as more cells fail. Lets assume based on a 'best guess' from the warranty and what I am reading on forums I am expecting my SSD to last me 3-5 years (much less than the 274 years of flash I have) under 'normal' to 'light' use conditions. This is a 1:91 to a 1:55 ratio from our calculations, which if applied to the second scenario means an expected life of 5-9 months on the hammered drive.

Obviously this is an extreme exaggeration, but I think the point is clear and striking: We need to get an appropriately sized SSD for our use. Getting a nice big one should add several extra years of use (assuming the controller or some other part does not die first), where as getting a drive too small that is always full will fail relatively quickly.


By the way; my wife has a 60GB SSD in her system (and a 500GB storage/documents drive), of which she is using 30GB, and has ~2-5GB workload per day (mostly Windows maintenance as all she does is e-mail, light browsing and some pandora). This comes to: 600TB of longevity/2.2TB of yearly use=272 years of use (lol, again; not very likely).
So I am not saying that small drives are useless, just that when moving to SSD you need a drive big enough for what you intend to use it for or you will run into major issues, and following the old HDD 80% usage rule is good to carry over to SSDs, though for very different reasons (for HDDs it was a performance issue as the inner 20% of the drive is useless and defragging becomes problematic on full drives, for SSDs it is a longevity issue).

*sigh* too long of a post... I just can't sleep.

 

[wrenaudrey]

Thank you CaedenV, very well explained-again
Would you say its better to consider other brand than OCZ for longetivity/cost/performance ratio?
Is Crucial's M4 and Samsung's 830 the latest ones-like OCZ's Petrol, Octane and Vertex 4?

 

[kajabla]

Crucial and Samsung are supposedly more reliable than OCZ, with Intel at the very top. I don't know how much truth there is to that right now except for Intel, which says it actually bins parts for reliability.

 

[wrenaudrey]

Best answer selected by Wrenaudrey.

 

[CaedenV]

if on a single drive system, or there are any concerns where a drive failure is going to cause you grief, then play it safe and get an M4 or Samsung. But as far as price/performance/reliability is concerned then the Agility 3 or Mushkin Chronos is the way to go at the moment.