New IMac 27' - SSD speed

Discussion in 'iMac' started by bmodi, Oct 13, 2015.

  1. bmodi macrumors member

    bmodi

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    #1
    Does one know the read/write speed of the SSD's used in the new 27' IMac?

    I suppose the speeds are different depending on the size of the SSD.
    Whats the spped of the 256GB and the 512GB SSD?
     
  2. Richie2000 macrumors 6502

    Richie2000

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    #2
    I was also wondering this. The press release states that SSD is up to 2.5 times faster than the previous generation

    http://www.apple.com/pr/library/201...Family-with-Stunning-New-Retina-Displays.html

    and the performance page on Apple.com states the following:

    For maximum performance, you can configure iMac with up to 1TB of PCIe-based flash storage that’s now up to 2.5 times faster than the previous version. Delivering up to 1800 Mbps of sequential read performance, pure flash storage is the fastest way to speed through the most demanding tasks.

    I am assuming from this that up to 1800Mbps applies to all sizes of SSD i.e. 256GB, 512GB and 1Tb.
     
  3. bmodi thread starter macrumors member

    bmodi

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    #3
    Hm, i am not sure....as far as i know depends the speed of the nvme-ssd technology also on the size of it.....means the 256GB size SSD is "slower" than the 512GB SSD?

    Maybe someone can clarify this?
     
  4. loekf, Oct 14, 2015
    Last edited: Oct 14, 2015

    loekf macrumors 6502

    loekf

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    #4
    According to Arstechnica:

    http://arstechnica.co.uk/apple/2015...ter-screen-21-5-inch-4k-retina-imac-reviewed/

    In the 21.5" model (Broadwell + some chipset) the SSD part of the Fusion drive and the SSD-only options connect via 4 PCIe 2.0 lanes and the speed should be comparable to a 2015 rMBP 13" model: 1400 MB/s read, 650 MB/s write. It's NVMExpress over 4x PCIe 2.0.

    21.5" is Broadwell, not sure how that will work out for the 27" Skylake model. Maybe the controller Apple is using is not the latest and greatest, so the rMBP model, and stuck at PCI 2.0 speeds.

    Nonetheless, the 2014 retina iMac did not have NVMexpress yet. It was introduced by Apple during the April 2015 macbook refresh. So SSDs should perform faster. Can't imagine it will do much for the 2015 Fusion drive with its "measely" 24 GB SSD.
     
  5. Richie2000 macrumors 6502

    Richie2000

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    #5
    Found an Arstechnica post on the 27 inch that seems to confirm.......

    http://arstechnica.com/apple/2015/10/apple-goes-all-retina-for-its-27-inch-skylake-imac-refresh/

    All solid-state storage in the new iMacs uses the NVMExpress interface that first showed up in the Retina MacBookearlier this year, and like the 13-inch Retina MacBook Pro they all have four PCIe 2.0 lanes' worth of bandwidth to work with, giving them data transfer speeds of up to 2GB per second.

    Looks like they do get the NVMExpress interface across the board! :)
     
  6. Samuelsan2001 macrumors 603

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    #6
    No the 256 runs about 1200Mbps the 512Gb about 15-1600MBps and the 1 Tb 1800Mbps.
     
  7. Richie2000 macrumors 6502

    Richie2000

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    #7
    That's good to know. I am looking to go with 512 SSD so 1200Mbps is a world away from my current iMac which is giving about 90Mbps on a spinner drive
     
  8. Jimmdean, Oct 14, 2015
    Last edited: Oct 14, 2015

    Jimmdean macrumors 6502

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    #8
    It should be noted that Ars looked at a fusion drive SSD - not the Samsung made SSD that made its way into the 15" Macbook Pro and presumably these new bto iMacs. Those SSDs are PCI 3.0, so as long as the interface is not nerfed on these new iMacs then SSD-only machines could/should see those same ridiculous speeds the 15" MBP have.

    On second thought - we might not see a SM951 SSD - we could see the Apple NVMExpress SSDs that were used in the base MacBooks. Those were also PCI 2.0. I guess we'll see...
     
  9. fob macrumors member

    fob

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    #9
    Whats the technical reason behind this?
     
  10. Richie2000, Oct 14, 2015
    Last edited: Oct 14, 2015

    Richie2000 macrumors 6502

    Richie2000

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    #10

    Ars had stated here (http://arstechnica.com/apple/2015/10/apple-goes-all-retina-for-its-27-inch-skylake-imac-refresh/) that the new 27" is using the NVMExpress SSDs. Not sure where they got this from but kinda hoping it is fact!

    All solid-state storage in the new iMacs uses the NVMExpress interface that first showed up in the Retina MacBookearlier this year, and like the 13-inch Retina MacBook Pro they all have four PCIe 2.0 lanes' worth of bandwidth to work with, giving them data transfer speeds of up to 2GB per second.
     
  11. Jimmdean macrumors 6502

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    #11
    That's not necessarily a good thing (right now). The new MacBook uses the NVMexpress interface, whereas the 15" MBP uses SATA express. With combination of interface and drive, the Macbook is not in the same league as the 15" MBP, being only PCI 2.0 and the MBP being PCI 3.0.
     
  12. Richie2000 macrumors 6502

    Richie2000

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    #12
    That's a good point Jimmdean, and one that I was not aware of. I'm still mulling over a 3Tb Fusion Drive versus a 512SSD config. I know the SSD is going to be quicker, period, but the benefit of all that extra storage built-in, coupled with 128Gb of SSD, is quite compelling. Going to hold off for a few weeks until we get some more "real-world" feedback I think
     
  13. gsingham macrumors 6502

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  14. Zellio macrumors 65816

    Zellio

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    #14
    Well ssds with bigger memory banks have more controllers and are generally faster. But This kind of jump in speeds for bigger ssds hasn't been seen in years, it's usually only around 50 mb/s faster for the larger ssds.

    If I had to guess, I'd guess that Tim Cook used cheaper memory for the 256 gb
     
  15. whodatrr macrumors 6502a

    whodatrr

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    #15
    Just wondering how much difference this bump would make for most of us, in our day to day lives?

    Coming from a 2013 3TB Fusion drive that never leaves me wanting. I love the capacity, and the stuff I use 95% of the time is available before I need it. Coming from a spinning disk, the difference was not subtle. My 2011 11.6 MBA ran circles around my 2010 27 iMac, with a 1TB spinner, due to its SSD. But my Fusion drive seems fast as Hell?

    I see tests with people writing scripts where they launch 30 apps simultaneously, and the SSD beats out the Fusion drive. But how hard will it be for us to tell the difference, in the real world?

    I ask because stepping down from 3TB to 512, or even 1TB, will be a hassle. Not to mention the extra cost, especially for the 1TB SSD.

    So, really, how much difference will we notice in the real world? Honest question... Just wondering if it's worth the expense and hassle?
     
  16. hifimacianer macrumors member

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    #16
    It all depends on how many Data you usually have in use.
    If most of your daily data is less than 128GB (the SSD part of the fusion drive), you won't notice any difference to a SSD only configuration. But if you often work with several big files, so the System has to read/write them from the spinning drive, you will notice a big difference.

    But there is one thing everyone has to consider before ordering a fusion:
    The biggest part of your data is still on a spinning drive, with all of it's downsides.
    I wouldn't trust a spinning drive that is older than 3 years, they tend to get slower and louder over time an will die a slow death. And it's really a pain to change the HD in the new iMacs.

    So I would always go the SSD-only way, even when it's only the 256GB model, and buy a external HD for your Data. If you use a compact 2,5" SSD, you can even hide it behind the screen without to see anything. I bought a 1TB Samsung 850 EVO and a 15$ UASP-capable USB 3 enclousure to use the max possible Speed of the SSD via USB. So there is even no need to buy a expensive Thunderbolt enclousure for that.
     
  17. deany macrumors 68020

    deany

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    #17
    Hi

    Crikey dont forget the 1TB fusion is:

    apple quote:
    'The 1TB Fusion Drive pairs a 1TB hard drive with 24GB'

    did you miss that (like I did) or were you talking about the 2 or 3 TB which is 128 GB?
     
  18. gsingham, Oct 15, 2015
    Last edited: Oct 15, 2015

    gsingham macrumors 6502

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    #18
    It strange. For me to move up to the 512gb model it's an add on cost of about $320AUD and for me to move up to the 1tb it's not $640AUd but close to $900AUD

    Where does the extra $260aud go?!?

    And the same with the memory

    The sweet spot seems to be 16gb and 512gb but not if the 512gb runs slower

    Doesn't the 512gb in the MacBook pros 2015 hit 1800mb/sec anyway?

    Even the 256gb in the MacBook Pro 2015 writes at 2.0gb/sec

    So I don't see any truth behind the 256 is slower than 1tb
     
  19. Richie2000 macrumors 6502

    Richie2000

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    #19
    Same applies in the UK. The uplift in price to 512Gb is £160, whereas 1TB is a whopping £560! Agree that the sweet spot seems to be 16gb memory and 512gb SSD but I still won't pay Apple prices for memory when I can do it myself for almost a £100 saving.
     
  20. deany macrumors 68020

    deany

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    #20
    on my rMBP 512gb Black magic max is 1550 to 1600 approx both read and write on the NTSC column.
     
  21. gsingham macrumors 6502

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    #21
  22. deany, Oct 15, 2015
    Last edited: Oct 15, 2015

    deany macrumors 68020

    deany

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    #22

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