Bringing You Up to Speed: The History Lesson

Everyone remembers their first bike right? Mine was red. It had training wheels. I never really learned how to ride it, not that I didn’t go outdoors, I was just too afraid to take those training wheels off I guess. That was a long time ago, but I remember my first bike.

I also remember my first SSD. It was a 1.8” PATA drive made by Samsung for the MacBook Air. It was lent to me by a vendor so I could compare its performance to the stock 1.8” mechanical HDD in the Air.

The benchmarks for that drive didn’t really impress. Most application tests got a little slower and transfer speeds weren’t really any better. Application launch times and battery life both improved, the former by a significant amount. But the drive was expensive; $1000 from Apple and that’s if you bought it with the MacBook Air. Buying it from a vendor would set you back even more. It benchmarked faster than hard drive, but the numbers didn’t justify the cost. I pulled the drive out and sent it back after I was done with the review.

The next time I turned on my MacBook Air I thought it was broken. It took an eternity to boot and everything took forever to launch. Even though the benchmarks showed the SSD shaving off a few seconds of application launch time here and there, in the real world, it was noticeable. The rule of thumb is that it takes about a 10% difference in performance for a user to notice. The application tests didn’t show a 10% difference in performance, but the application launch tests, those were showing 50% gains. It still wasn’t worth $1000, but it was worth a lot more than I originally thought.

It was the MacBook Air experience that made me understand one important point about SSDs: you don’t think they’re fast, until I take one away from you.

My second SSD was a 60GB SuperTalent drive. I built a HTPC using it. It was my boot drive and I chose it because it drew less power and was silent; it helped keep my HTPC cool and I wouldn’t have to worry about drive crunching while watching a movie. My movies were stored elsewhere so the space didn’t really matter. The experience was good, not great because I wasn’t really hitting the drive for data, but it was problem-free.

SuperTalent was the first manufacturer to sell a SSD in a 3.5” enclosure, so when they announced their 120GB drive I told them I’d like to do a review of their SSD in a desktop. They shipped it to me and I wrongly assumed that it was the same as the 60GB drive in my HTPC just with twice the flash.

This drive did have twice the flash, but it was MLC (Multi-Level Cell) flash. While the 60GB drive I had was a SLC drive that used Samsung’s controller, the MLC drive used a little known controller from a company called JMicron. Samsung had a MLC controller at the time but it was too expensive than what SuperTalent was shooting for. This drive was supposed to be affordable, and JMicron delivered an affordable controller.

After running a few tests, the drive went in my Mac Pro as my boot/application drive. I remembered the lesson I learned from my first SSD. I wasn’t going to be able to fairly evaluate this drive until I really used it, then took it away. Little did I know what I was getting myself into.

The first thing I noticed about the drive was how fast everything launched. This experience was actually the source of my SSD proof-of-value test; take a freshly booted machine and without waiting for drive accesses to stop, launch every single application you want to have up and running at the same time. Do this on any system with a HDD and you’ll be impatiently waiting. I did it on the SuperTalent SSD and, wow, everything just popped up. It was like my system wasn’t even doing anything. Not even breaking a sweat.

I got so excited that I remember hopping on AIM to tell someone about how fast the SSD was. I had other apps running in the background and when I went to send that first IM and my machine paused. It was just for a fraction of a second, before the message I'd typed appeared in my conversation window. My system just paused.

Maybe it was a fluke.

I kept using the drive, and it kept happening. The pause wasn’t just in my IM client, it would happen in other applications or even when switching between apps. Maybe there was a strange OS X incompatibility with this SSD? That’d be unfortunate, but also rather unbelievable. So I did some digging.

Others had complained about this problem. SuperTalent wasn’t the only one to ship an affordable drive based on this controller; other manufacturers did as well. G.Skill, OCZ, Patriot and SiliconPower all had drives shipping with the same controller, and every other drive I tested exhibited the same problem.

I was in the midst of figuring out what was happening with these drives when Intel contacted me about reviewing the X25-M, its first SSD. Up to this point Intel had casually mentioned that their SSD was going to be different than the competition and prior to my JMicron experience I didn’t really believe them. After all, how hard could it be? Drive controller logic is nowhere near as complicated as building a Nehalem, surely someone other than Intel could do a good-enough job.

After my SuperTalent/JMicron experience, I realized that there was room for improvement.

Drive vendors were mum on the issue of pausing or stuttering with their drives. Lots of finger pointing resulted. It was surely Microsoft’s fault, or maybe Intel’s. But none of the Samsung based drives had these problems.

Then the issue was cache. The JMicron controller used in these drives didn’t support any external DRAM. Intel and Samsung’s controllers did. It was cache that caused the problems, they said. But Intel’s drive doesn’t use the external DRAM for user data.

Fingers were pointed everywhere, but no one took responsibility for the fault. To their credit, OCZ really stepped up and took care of their customers that were unhappy with their drives. Despite how completely irate they were at my article, they seemed to do the right thing after it was published. I can’t say the same for some of the other vendors.

The issue ended up being random write performance. These “affordable” MLC drives based on the JMicron controller were all tuned for maximum throughput. The sequential write speed of these drives could easily match and surpass that of the fastest hard drives.

If a company that had never made a hard drive before could come out with a product that on its first revision could outperform WD’s VelociRaptor and be more reliable thanks to zero moving parts...well, you get the picture. Optimize for sequential reads and writes!

The problem is that modern day OSes tend to read and write data very randomly, albeit in specific areas of the disk. And the data being accessed is rarely large, it’s usually very small on the order of a few KB in size. It’s these sorts of accesses that no one seemed to think about; after all these vendors and controller manufacturers were used to making USB sticks and CF cards, not hard drives.

  Sequential Read Performance
JMicron JMF602B MLC 134.7 MB/s
Western Digital VelociRaptor 300GB 118 MB/s

 

The chart above shows how much faster these affordable MLC SSDs were than the fastest 3.5” hard drive in sequential reads, but now look at random write performance:

  Random Write Latency Random Write Bandwidth
JMicron JMF602B MLC 532.2 ms 0.02 MB/s
Western Digital VelociRaptor 300GB 7.2 ms 1.63 MB/s

 

While WD’s VelociRaptor averaged less than 8ms to write 4KB, these JMicron drives took around 70x that! Let me ask you this, what do you notice more - things moving very fast or things moving very slow?

The traditional hard drive benchmarks showed that these SSDs were incredible. The real world usage and real world tests disagreed. Storage Review was one of the first sites to popularize real world testing of hard drives nearly a decade ago. It seems that we’d all forgotten the lessons they taught us.

Random write performance is quite possibly the most important performance metric for SSDs these days. It’s what separates the drives that are worth buying from those that aren’t. All SSDs at this point are luxury items, their cost per GB is much higher than that of conventional hard drives. And when you’re buying a luxury anything, you don’t want to buy a lame one.

  Cost Per GB from Newegg.com
Intel X25-E 32GB $12.88
Intel X25-M 80GB $4.29
OCZ Solid 60GB $2.33
OCZ Apex 60GB $2.98
OCZ Vertex 120GB $3.49
Samsung SLC 32GB $8.71
Western Digital Caviar SE16 640GB $0.12
Western Digital VelociRaptor 300GB $0.77
Index Why You Should Want an SSD
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  • Gasaraki88 - Friday, March 20, 2009 - link

    RAID is a universal standard so if you take two RAID0 drives out and move them to another computer with a RAID controller, it SHOULD just work if the original RAID was doing it correctly. Reply
  • coil222 - Wednesday, March 18, 2009 - link

    Yes I run a pair of MTRON 7500s in a raid 0 stripe for my OS and Gaming (wow). I don't recall numbers off the top of my head but tests were better on the raid 0 than a single drive configuration.

    Watch this:
    http://www.youtube.com/watch?v=96dWOEa4Djs&fea...">http://www.youtube.com/watch?v=96dWOEa4Djs&fea...
    Reply
  • sawyeriii - Wednesday, March 18, 2009 - link

    I just wanted to state how much I loved the combination of technical and real world information in this article.

    What is the possibility of having different page sizes built into a drive? I.e. you could have a drive with many 1k page packages on one die, 2k on another, and most others 4k. Could that theoretically help? Could the controllers work with that (or would you need to combine multiple 1k's into a 4k transfer size)?

    PS One note on page 3, the VelociRaptor and Intel in the first chart (responce time) are switched, however the text is correct.
    Reply
  • StormyParis - Wednesday, March 18, 2009 - link

    the ugly truth is that an SSD won't let you do anything that you couldn't do without it, and due to its cost and small capacity, it's not a replacement drive, it's an extra drive: not less power consumption but more, not less noise but just the same. You just gain a bit of time when booting up and lauching apps... which I do about 1/week and 1/day, respectively. Assuming your system has enough RAM (and if it doesn't, buy RAM before buying an SSD !), you won't feel much difference once the apps are launched.

    For the same cost, I'd rather buy a bigger screen.

    It's urgent to wait for prices to come down. But I'm all for lots of people buying them now and help get the price down for us wiser buyers.
    Reply
  • Rasterman - Thursday, March 19, 2009 - link

    I've already decided my next system in a few months will have one, after you go through 5 hard drive failures (over several years) lets see how much your willing to pay to not have to put up with it anymore. If you use your PC for anything useful (work) then an SSD is a no brainer even at $1000/64GB IMO if the data security is there, speed is secondary for me.

    When you already have the best screen, video card, memory, why not have the best drive? And your argument is pretty dumb, almost any upgrade won't let you do anything that you couldn't do without it, not just SSDs.
    Reply
  • Calin - Wednesday, March 18, 2009 - link

    You get lower power due to the lower power use of the SSD and the fact that the other drive is not stressed with difficult access patterns (small random reads/writes). Remember that idle power of a SSD drive is very low Reply
  • 7Enigma - Wednesday, March 18, 2009 - link

    No, his comment was accurate for most users. Due to the small capacities and high cost these will be used as boot drives primarily with maybe a single heavily used program (say the current game or program you are playing/using), the rest will be on an additional drive. So while the power consumption of the SSD would be less than the old drive, the aggregate power usage of both (even when the larger storage drive is primarily at idle) will be higher than the single HD.

    And I believe you meant to say traditional HD for idle power?
    Reply
  • strikeback03 - Wednesday, March 18, 2009 - link

    If all you were going to throw on the drive is the OS and a game, a 32GB drive should be plenty. The reason the 80GB and up range is important is so general consumers can load all their programs on it.

    But yes, in consumer usage other than a laptop, some people who were previously using one drive for both boot and storage would likely need a mechanical HDD is addition to the SSD. OTOH, those who were using a Velociraptor (or RAID array) for boot and another drive for storage will see their power consumption decrease.
    Reply
  • sawyeriii - Wednesday, March 18, 2009 - link

    Have you used a SSD? (If so which)

    I would state that it is not a luxary product, it is a premium product. The price difference you pay WILL translate to faster performance (if you choose correctly). More RAM only helps upto a point.

    Remember performance is based on a system of parts...
    CPU
    RAM
    NORTHBRIDGE
    GPU
    SOUTHBRIDGE
    I/O INTERFACE
    HDD/SDD

    Microsoft's Windows Experience Index has specific flaws, but the concept is sound... The system can only go a fast as the slowest component in the system (relative to the amount of time used by that component).
    Reply
  • Testtest - Wednesday, March 18, 2009 - link

    ... there's also Supertalent's Ultradrive ME (MLC) and LE (SLC) and Photofast's G-Monster v3

    At least the Supertalent drives are quite a bit cheaper with the same drive layout/controller than the Vertex drives and only differ in the firmware (which isn't bad either).

    It's however possible at least with the Ultradrive ME currently to provoke a kinda timeout error after they've been fully filled once and then still beeing written on. I don't own a Vertex so I can't test that there but if it was a controller issue, it should pop up there sooner or later as well (if you take a look in their suppport forum some error reports seem very similar).

    Intels have their 80% bug, Indilinx drives have their issues too it seems - let's hope that firmware can cure it!

    Great article btw!
    Reply

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