The SSD Relapse: Understanding and Choosing the Best SSD
by Anand Lal Shimpi on August 30, 2009 12:00 AM EST- Posted in
- Storage
One Tough Act to Follow
What have I gotten myself into? The SSD Anthology I wrote back in March was read over 2 million times. Microsoft linked it, Wikipedia linked it, my esteemed colleagues in the press linked it, Linus freakin Torvalds linked it.
The Anthology took me six months to piece together; I wrote and re-wrote parts of that article more times than I'd care to admit. And today I'm charged with the task of producing its successor. I can't do it.
The article that started all of this was the Intel X25-M review. Intel gave me gold with that drive; the article wrote itself, the X25-M was awesome, everything else in the market was crap.
Intel's X25-M SSDs: The drives that started a revolution
The Anthology all began with a spark: the SSD performance degradation issue. It took a while to put together, but the concept and the article were handed to me on a silver platter: just use an SSD for a while and you’ll spot the issue. I just had to do the testing and writing.
OCZ's Vertex: The first Indilinx drive I reviewed, the drive that gave us hope there might be another.
But today, as I write this, the words just aren't coming to me. The material is all there, but it just seems so mature and at the same time, so clouded and so done. We've found the undiscovered country, we've left no stone unturned, everyone knows how these things work - now SSD reviews join the rest as a bunch of graphs and analysis, hopefully with witty commentary in between.
It's a daunting, no, deflating task to write what I view as the third part in this trilogy of articles. JMicron is all but gone from the market for now, Indilinx came and improved (a lot) and TRIM is nearly upon us. Plus, we all know how trilogies turn out. Here's hoping that this one doesn't have Ewoks in it.
What Goes Around, Comes Around
No we're not going back to the stuttering crap that shipped for months before Intel released their X25-M last year, but we are going back in the way we have to look at SSD performance.
In my X25-M review the focus was on why the mainstream drives at the time stuttered and why the X25-M didn't. Performance degradation over time didn't matter because all of the SSDs on the market were slow out of the box; and as I later showed, the pre-Intel MLC SSDs didn’t perform worse over time, they sucked all of the time.
Samsung and Indilinx emerged with high performance, non-stuttering alternatives, and then we once again had to thin the herd. Simply not stuttering wasn't enough, a good SSD had to maintain a reasonable amount of performance over the life of the drive.
The falling performance was actually a side effect of the way NAND flash works. You write in pages (4KB) but you can only erase in blocks (128 pages or 512KB); thus SSDs don't erase data when you delete it, only when they run out of space to write internally. When that time comes, you run into a nasty situation called the read-modify-write. Here, even to just write 4KB, the controller must read an entire block (512KB), update the single page, and write the entire block back out. Instead of writing 4KB, the controller has to actually write 512KB - a much slower operation.
I simulated this worst case scenario performance by writing to every single page on the SSDs I tested before running any tests. The performance degradation ranged from negligible to significant:
| PCMark Vantage HDD Score | New | "Used" |
| Corsair P256 (Samsung MLC) | 26607 | 18786 |
| OCZ Vertex Turbo (Indilinx MLC) | 26157 | 25035 |
So that's how I approached today's article. Filling the latest generations of Indilinx, Intel and Samsung drives before testing them. But, my friends, things have changed.
The table below shows the performance of the same drives showcased above, but after running the TRIM instruction (or a close equivalent) against their contents:
| PCMark Vantage HDD Score | New | "Used" | After TRIM/Idle GC | % of New Perf |
| Corsair P256 (Samsung MLC) | 26607 | 18786 | 24317 | 91% |
| OCZ Vertex Turbo (Indilinx MLC) | 26157 | 25035 | 26038 | 99.5% |
Oh boy. I need a new way to test.
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jasperjones - Monday, September 7, 2009 - link
Bit of a late reply to your question but a single overwrite with random data is fully secure. At least for HDDs there have been tests from academics that tried to recover data from a HDD after wiping it via "dd if=/dev/urandom bs=1M" They weren't able to recover anything.smjohns - Thursday, September 3, 2009 - link
Great 3rd installment and I have learnt more about SSD's from this site than any other !!Whilst there is no doubt that Intel G2 definitely remains the SSD drive of choice (assuming you have the cash). Why did Intel choose not to address the poor sequential write speeds? In the above tests it seems no better than a standard 5400 hard disc....which is a little poor. I accept it is blisteringly fast for everything else but not sure why this was ignored / shelved?
Is it that it is currently impossible to build a drive that can be fast at both large sequential and small random file writes? Or is it that the G2 was always intended to be an incremental improvement over the G1 (fixing some of its short comings) rather than a complete top to bottom redesign of the unit, which may have lead to this being addressed? As such could a future firmware release improve these speeds....or is it definitely a hardware restriction?
I have to say I am personally torn between the OCZ Vertex and Intel G2 at the moment. Whilst I accept the G2 seems to be the quicker drive in the real world, I was disappointed that they did not improve the sequential write speeds and in addition to this, they do seem a little slow with support. The OCZ on the other hand seems a bit of an all rounder and not that much slower than the G2. In addition to this I REALLY like OCZ's approach to supporting these drives and they really seem to listen to their customers feedback.
One final question....when installing an SSD into a laptop with a fresh Windows 7 install, is there now any need for special formatting / OS settings to ensure best drive performance / life? There is a lot of stuff on the web but it all seems particularly relevant for XP and partially Vista but I was under the impression that Win7 was designed to work with SSDs out of the box?
derkurt - Thursday, September 3, 2009 - link
Then, there is another reason why SSDs are not covered extensively by the mainstream press: They are too complicated.Let's say you want to buy a hard disk. You could just buy any hard disk, since the difference between good and bad ones is fairly small. If you buy an ExcelStor, for example, you will still get something which works and delivers sufficient performance compared to faster models. Unless you are looking at the server market, there is not that much difference at all. Some models have larger caches, faster seek times and higher transfer rates due to higher rotational speeds, but the main difference is capacity, so the market is transparent.
Now look at the SSD market: The difference between good and bad ones is huge, incredibly huge. The Intel G2 is lightning fast while some old JMicron-based drives are much worse than a 5-years-old hard disk. You can't just go and buy "an SSD". You need to be informed:
What controller is the SSD using? Do I have to align my partitions, or is my operating system detecting the SSD and doing that for me? Does my OS support TRIM? Does my AHCI driver support TRIM? Does my SSD support TRIM? Does my current firmware revision support TRIM, and if so, do I need to flash a beta firmware which still has some serious flaws in it? How is the performance degradation after heavy use? What about random write access times (very big differences here which strongly affect real world performance)?
If you don't care about the above, chances are you will get a crappy drive. And even if you do, you'll have a hard time finding out some essential facts (thanks Anand!), since the manufacturers aren't exactly putting them on their webpages. They will tell you the capacity and the maximum linear transfer rates. That's all, basically. You will have to do some exhaustive googling to investigate what controller the drive is using, whether the firmware supports TRIM, and so on. Even Intel is holding back with detailed information, though they wouldn't have to, since they have nothing to hide as their drives are the fastest in nearly all aspects.
I don't know for sure why the manufacturers are making a secret out of essential information, even if they can shine there. But there's one thing I do know: Only when people don't need to care about controllers, OS support, firmwares etc. anymore, SSDs are ready to hit the mainstream.
smjohns - Thursday, September 3, 2009 - link
I fully agree with you here and it is one of the reasons why I have not taken the plunge yet. I am definitely holding out for Win7 and then upgrade my laptop with both that and an SSD.Even after reading these great articles, whilst I now know which drives support Trim and the fact that none of them have this functionality fully enabled and will require a future firmware update ("shudders"), the SSD market is indeed a confusing place to be. And thats before you consider having to align partitions (what the heck is this) and the various settings in the BIOS / OS you need to enable / disable to ensure your lovely new drive does not die within a few weeks / months / years.
If the industry really does want widespread adoption of these new drives, it needs to resolve these issues and come up with some easy and readily available standards we can all follow. I just hope Win7 is as SSD friendly as we are led to believe.
derkurt - Thursday, September 3, 2009 - link
AFAIK, "aligning" partitions means that the logical layout of blocks has to match the physical block assigment on the SSD in a certain way, otherwise writing one logical block on the filesystem level may result in an unnecessary I/O operation covering two blocks on the SSD (because the logical block spans the boundaries between two physical blocks). But don't ask me for details, I haven't dug into that yet.
According to MS, Windows 7 detects SSDs and applies a proper alignment scheme automatically during installation of the OS. If you'd like to install a Linux distribution or an older version of Windows, you'll probably have to take care of that by yourself, unfortunately.
I guess there aren't that many, you should just turn on AHCI support - the drive will work without it, but you need it for enabling NCQ, which can give you a 5-10% performance boost. However, you need to do this before the OS installation, otherwise your OS might cease to boot. Oh, and also you may have to temporarily turn off AHCI support when flashing a new firmware, because some flashing tools are struggling of AHCI is turned on.
I hope that with the advent of Windows 7 going into public sale, SSD manufacturers will start to ship reliable, TRIM-enabled firmware revisions. If so, you shouldn't have to think about all these issues anymore as long as you are using Windows 7.
derkurt - Thursday, September 3, 2009 - link
I was one of the lucky guys to get an Intel G2 drive before they stopped shipping it for a while, and I can absolutely confirm everything Anand states about performance.However, I still wonder why there is relatively few competition out there. At least in theory, it takes far less know-how to produce a good SSD than is required to manufacture reliable hard disk drives - think about the expansive and complicated fine mechanics involved. Actually, there are some Chinese manufacturers most of us have never heard of, such as RunCore, which manage to deliver SSDs of at least usable quality.
Where is the Samsung drive that blows the competition away? What about Seagate, Western Digital, Hitachi? Are they just watching from the sideways while SSDs from some young and small companies are cannibalizing their markets?
At the time the shift from CRTs to LCDs was taking place, German premium TV manufacturer Loewe estimated that it would take many years until CRTs became obsolete. But the change happened so fast it nearly blew off their business before they finally started to ship high-quality LCDs in response to market demand. It seems to me that the very same thing is happening again now.
The G2 is gorgeous, no doubt about it. But the price point is still way above being ready to hit the mainstream. Computers are simply not important enough to Joe Sixpack to spend 200+ USD for storage solutions only, even if it _really_ accelerates the machine (something most people won't believe until they experienced it themselves), and especially considering the low capacities offered by SSDs so far.
If something as great as the G2 can be offered for 240 USD while being sold to a relatively small audience, what prices can we expect to see if the mainstream is hit? If USB sticks can be sold for less than 5 USD, what is the fundamental problem at reaching a price point of 60 USD for high-quality SSDs? Of course, SSDs contain much more intelligence than USB pen drives: Multi-channel controllers with sophisticated strategies, caches, and so on, but the main difference should be the effort required to engineer these devices, rather than the cost for building them.
I am a bit frustrated that while there are SSDs available now which deliver superior performance, they still cover a small niche of enthusiasts (and there are probably a lot more people who would want to buy one if they only knew that these things exist), and the traditional hard drive manufacturers cease to join the game. The most important reason why Intel priced the G2 at a more affordable level is probably not the competition by Indilinx drives, but rather the idea that they can gain more profit by selling much more drives, even if they are sold at a lower price, as long as production costs are fairly small.
Is Samsung sleeping, or are they just fearing that the shift to SSDs might destroy their mechanical hard drive business? I doubt that they don't have engineers capable of creating SSDs which deliver a performance comparable to Intel's drives. Maybe the mediocre performance of their SSDs is part of a strategy, which says that SSD development shouldn't be pushed too fast until the rest of the market is really forcing them to do so.
Companies such as Apple need to sell good SSDs with their computers, by default. Why can't premium PC manufacturers like Apple sell their hardware with a G2 drive, while they are offering similarly expansive CPUs? If you are spending the 240 USD for a CPU upgrade instead, I'd take every bet that you were unable to feel a comparable performance gain. It's a shame that PC sellers are neglecting hard drive performance while at the same time stressing the CPU power of their systems in their advertisements. Only if Seagate & Co. realize that they are losing a large and growing market share by not joining the SSD race, prices will drop. So far, they just don't care about some hardware geeks like us.
pepito - Monday, November 16, 2009 - link
There are a bunch of companies selling SSD already, its just that you don't know where to find them, and most reviewers only care about big players, such as Intel or Samsung.If you check, for example, http://kakaku.com/pc/ssd/">http://kakaku.com/pc/ssd/ you can see there are currently 24 manufacturers listed there (use google translate, as its in japanese).
Some you probably never heard of: MTRON, Greenhouse, Buffalo, CFD, Wintec, PhotoFast, etc.
iwodo - Thursday, September 3, 2009 - link
I have trouble understanding WHY Apple, uses Samsung CRAPPY SSD like everyone else when they could easily make their own.And SSD drive, like all Indlinx drive, are nothing more then Flash Chip soldered on to PCB with Indilinx Core. Apple is already the largest Flash buyer in the world, they properly buy the cheapest Flash memory in the market. ( Intel and Samsung of coz don't count since they make the flash themselfs. ) Building an SSD themself would be adding $20 dollars on top of 8 Chips 64Gb Flash.
Why they dont build one and use it accross its Mac is beyond me. Since even the firmware is the same as everyone else.
pepito - Monday, November 16, 2009 - link
For the same reason that Dell doesn't make their own batteries, its not their business.Borski - Thursday, September 3, 2009 - link
How does G.skill Falcon compare with the reviewed units? I've seen very good reviews (close to Vertex) elsewhere but they don't mention things like used vs new performance, or power consumption.I'm considering buying the G.Skill Falcon 64G, which is cheaper than Agility in some places.