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Performance Showdown - SSDs vs. HDDs

Posted by timothy on from the all-those-Ds-at-once dept.

Lucas123 writes "Computerworld compared four disks, two popular solid state drives and two Seagate mechanical drives, for read/write performance, bootup speed, CPU utilization and other metrics. The question asked by the reviewer is whether it's worth spending an additional $550 for a SSD in your PC/laptop or to plunk down the extra $1,300 for an SSD-equipped MacBook Air? The answer is a resounding No. From the story: "Neither of the SSDs fared very well when having data copied to them. Crucial (SSD) needed 243 seconds and Ridata (SSD) took 264.5 seconds. The Momentus and Barracuda hard drives shaved nearly a full minute from those times at 185 seconds. In the other direction, copying the data from the drives, Crucial sprinted ahead at 130.7 seconds, but the mechanical Momentus drive wasn't far behind at 144.7 seconds."

9 of 259 comments (clear)

  1. bad test by Werrismys · · Score: 5, Insightful

    In typical use most of the time is spent seeking, not just reading or writing sequential blocks. The Windows XP disk IO is especially brain damaged in this regard (does not even try to order or prioritize disk I/O). Copying DVD images from one drive another is not typical use case.

    --
    'Once scientists, even the dim-witted social scientists, get muzzled, the Western Civilization is finished.' - oldhack
    1. Re:bad test by SanityInAnarchy · · Score: 4, Interesting

      Consider, also, that when you're doing anything other than the contrived "copy from one device to another"... HD-DVD has a minimum guaranteed throughput of something like 30 mbits, Blu-Ray needs 50. It looks like the worst numbers on the solid state devices were still at least some 30 megabytes per second, meaning you could play five Blu-Ray movies at once.

      Skimming the article, it seems very likely that the person responsible has read just enough to be dangerous (they know the physics of why seeking is slow), but not enough to have a clue what kind of behavior would trigger seeking. The one measure was boot time, during which they acknowledge that Vista does a bunch of background stuff after boot, but don't measure it.

      He did get one thing right, though -- they are not exactly living up to their potential. For one thing, there are filesystems explicitly designed for flash media, but you need to actually access it as flash (and the filesystem does its own wear leveling) -- these things pretend to be a hard disk, and are running filesystems optimized for a hard disk, so the results are not going to be at all what they could be.

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    2. Re:bad test by ThePhilips · · Score: 4, Interesting

      XP IO subsystem is pretty OK.

      The problem with SSD is that flash based storage has much much higher block size.

      While conventional HDDs have block size 512 bytes, actual SSDs have block size of 64 kilobytes.

      Not only Flashes write relatively slow, but if file system has e.g. cluster size of 8K, every write to it in worst case would also (re)write redundantly 64K-8K=56K.

      Test is realistic - if you want to see how bad most applications can be with SSDs. But that's going to change with SSD becoming more and more common place.

      If they really wanted to test SSD performance they would have taken Linux with jffs2 or newer logfs. Though this two have their own problems.

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  2. Untested performance... by smitty97 · · Score: 4, Interesting

    Unfortunately there's no comparisons of battery life and speed tests with fragmented files.

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  3. Not very good reasons... by MrKevvy · · Score: 4, Insightful

    Computerworld compared four disks, two popular solid state drives and two Seagate mechanical drives, for read/write performance, bootup speed, CPU utilization and other metrics.

    But of course not the metrics that really matter, which SSD's vastly excel at and make them worth the price for many people: MTBF, power consumption, ruggedness and noise level.

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    1. Re:Not very good reasons... by Mordok-DestroyerOfWo · · Score: 5, Insightful

      If I remember correctly the first LCD monitors were exorbitantly expensive and couldn't hold a candle to their CRT brothers. But since they saved so much space and energy, within a few years those problems vanished. I'd say it's still too early to close the books on SSDs.

      I know it's not a car analogy, I humbly beg the forgiveness of the /. community.

      --
      "Never let your sense of morals prevent you from doing what is right" - Salvor Hardin
  4. Stupid Test by phantomcircuit · · Score: 4, Informative

    They only tested burst speeds, there was no random access testing.

    SSD works best when accessing files randomly.

  5. SSDs are ideal for servers by ncw · · Score: 4, Insightful

    As any sysadmin knows, on a busy server what creams the disk isn't Megabytes per second, it is IO transactions per second.

    According to the article the Crucial SSD has an access time of 0.4 ms which equates to 2500 IOs/s as compared to the Barracuda HDD with 13.4 ms access time which equates to a mere 75 IOs/s.

    So for servers SSDs are 33 times better!

    Bring them on ;-)

    --
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  6. Seek Times Make the Difference by pancrace · · Score: 5, Interesting

    We installed one of these for processing millions of small, read-only database transactions. The database only gets written once a day, but is too big for efficient cacheing. Even with a U320 15k drive we were still suffering, only being able to run about 700/min. With a flash drive, we're running over 25,000/min, peaking at 50,000/min. But the weekly copy of the database takes about 20 minutes, vs the 3 or 4 minutes it used to take.

    - p

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