2011 iMac 27" HDD Slow

Discussion in 'iMac' started by Sam0r, Feb 26, 2012.

  1. Sam0r macrumors regular

    Jun 15, 2005
    Birmingham, UK
    Since I got my new iMac last year I've always throught it felt a bit slow. Although I put up with it and eventually got used to it.

    Although I've just been looking into SSDs etc and noticed people are using a benchmark tool by Blackmagic design called Disk Speed Test (How apt..)

    Anyway, I'm only getting between 70MB/s and 80MB/s on read AND write.

    My old iMac used to get way higher than that, around 100MB/s on read and about 70MB/s on the write. That was a late 2006 24" model with a 500g WD hard drive.

    Is there anything I can do about this? The drive in my iMac is the WDC WD1001FALS-403AA0 and it's linked at 3gb/s.

    I'm sure I've had much higher performance out of 1t drives...

    Anyway, is there anything I can do about this short of getting a better drive/SSD? I know a few drives come with power saving, so they actually run slower to save power, run cooler and quieter. But I'd much rather have the performance than a quiet hard drive. Most hard drives these days are quiet anyway.
  2. macmastersam macrumors 6502a

    Sep 14, 2011
    Essex, england
    I would suggest getting an SSD like you mentioned. and from what you said it looks like you want to get a new hard drive... i would either get this or just get the ssd if you have the money...
  3. Sam0r thread starter macrumors regular

    Jun 15, 2005
    Birmingham, UK
    First off, I'm not spending any money. I don't need the performance of an SSD, but I do need the sapce. I use logic etc and I hate the thought of having to bodge an SSD in there. I just want my iMac to perform the way it should.

    I've just asked a friend of mine who has the previous generation 27" iMac to do a benchmark using the same software I was and he's getting 120MB/s read. That's 40MB/s difference, which would be noticeable.

    I think I'm going to get apple to take a look at it since it's still in warranty.
  4. Ccrew macrumors 68020

    Feb 28, 2011
    Blackmagic uses uncompressible data to render its tests, the numbers you're seeing are correct, and an SSD would read low using that program for test also. BlackMagic only recently changed the way that they did their data scores, so even if comparing it to a test run 6 months ago it may well have been a different version of the program.

    Keep in mind that the numerical tests are for the most part only valid if you're using the same program for all your tests and all the published numbers out there. That's not the case. It behooves the manufacturers and sellers to use whatever test that provides the highest number in a shootout. It's not that your drive is slow, it's that the benchmark you're using is different is all. My 27" scores exactly the same as yours with BlackMagic.

    You can take it into an Apple store, that's your prerogative, but if the drive tests non-corrupt and the SMART flags aren't tripped then it's not a warrantable repair because you think it's "slow"
  5. lamboman macrumors 6502

    Aug 13, 2011
    Just to confirm what everybody else has said, the speeds that you are seeing are normal.

    You could try defragmenting the drive, fixing permissions if you are having major lag issues (this sometimes does fix things, it's a tad strange), but beyond this, your iMac is fine.

    The SSD upgrade is your best bet if you want increased speed. You could use a 64GB drive (Crucial m4 for example) as your boot drive, then use your standard drive as your storage drive. However, this might prove to be more work than it is worth.
  6. Sam0r thread starter macrumors regular

    Jun 15, 2005
    Birmingham, UK
    So why is my friends iMac which is a year older than mine getting higher results? I'd expect to see about 120-140MB/s from this drive.

    We ran the tests at the same time. Mine is a higher spec than his too, his is only a C2D with 4gb of ram, Mine is an i5 2.7 quad with 8gb of ram.

    I'm in windows at the moment and I get slightly higher results with Crystal disk mark (around 90MB/s).

    The drive checks out fine, I'm starting to wonder if its a partition alignment issue.


    I don't think it's slow, it IS slow. Not just by numbers either. Trust me I've been in this game enough time to know what kind of speed I should be "feeling" from a machine of this spec even on windows.

    That said, I've never run SL on this iMac, so maybe its Lion that's slow. Having said that Window's takes forever to boot just like OS X does.
  7. Taz Mangus macrumors 68040

    Taz Mangus

    Mar 10, 2011
    Give AppleCare a phone call and they can probably help you resolve your issue your having. That is what I would do.
  8. motorazr macrumors 6502


    Oct 24, 2006
    The Frozen Waste...wait. Duluth, Minnesota.
    I hate to bump this since I don't think it'd been going anywhere, but ---

    I too have a 2011, 27" iMac with a 1TB hard drive, and I feel its INCREDIBLY slow.

    Using Xbench to compare drive read and write speeds, I can find that my iMac averages at 98 points, meaning it's slower than their base model for comparison (a 2005 G5 mac)... while my MacBoor Air (yes, I know .. SSD should hold a fair advantage..) achieves a drive average of 345 points, and my poor 5 year old external 320GB laptop drive, connected over USB, scores 49 points.

    Now I know points are irrelevant, but the thing is, my iMac's lowest drive speeds were the uncached read and write (4k blocks), coming in at 0.98MB/s and 2.49MB/s respectively, leaving the uncached write FAR below the base benchmark recorded by their program.

    What gives with this? I find that if I run photoshop once with a few images, save, then quit photoshop, I can't use my iMac without restarting because I'll wait for 30 seconds for Safari to load out of swap space (since I donate 9GB ram to photoshop.. I'm pretty sure everything else gets moved to the background)... and each tab I try to open its just a delay and lots of hard drive noise as it works. I've run disk warrior, and that certainly didn't help... but ideas? I've owned quite a few macs in the past and I've never had this issue of running a large program (such as photoshop or premier or lightroom) and not being able to get the computer out of the slow feeling without such a hassle, not to mention if I'm in photoshop it will often start acting this way within a very short period of time (as in, minor adjustments take seconds of the loading icon to process, yet my processor is nearly idle, and the actual visual effect of the transformation or effect is instant).

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