Read/Write Speeds?

Discussion in 'MacBook' started by tom vilsack, Apr 16, 2015.

  1. tom vilsack macrumors 68000

    tom vilsack

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    #1
    Just reading a article about samsung's new SM951-NVMe with read/write speeds of.... read speeds of 2,260MB/s and write speeds of 1,600MB/s.

    What are the read/write speeds of the new MacBook?

    ref: Samsung
     
  2. newellj macrumors 601

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    #2
    I ran my 1.2/512. I got around 450mb/s read and 790mb/s write.

    [​IMG]
     
  3. Cvx5832 macrumors regular

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    Nov 2, 2014
    #3
    I get about the same as above with FV2 active. I have my MB set up to my liking now. I mention this because I have several programs in the background which may/may not be using the disk or CPU during the test.

    To those getting goofy reads and writes from this specific app, just let it run. In a few cycles you'll see it posting the "full" amounts. Whether that means there's still firmware improvements to be had on the SSD or whether the app itself just needs to be optimised for the new MB in a future version, I don't know.

    [​IMG]
     
  4. tom vilsack thread starter macrumors 68000

    tom vilsack

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    #4
    That seems rather slow no? The new air get's write speeds of 629.9MB/s and average read speeds of 1285.4MB/s.

    I wonder why Apple didn't include the air's ssd...or the (above link) samsung's super fast new SM951-NVMe.
     
  5. Cvx5832 macrumors regular

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    #5
    It's slow for spec-whores. In real world use you'll probably never notice that.
     
  6. newellj macrumors 601

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    #6
    1. 4-channel vs 2-channel PCI-e.

    2. Arguably irrelevant except for measurbating. The rest of the system is going to come into play in real life and is not fast enough to really get any benefits out of 1200+ mb/s.
     
  7. ccsasuke macrumors newbie

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    Apr 9, 2015
    #7
    As a spec whore myself, I actually posted several times on the SSD. The speed made me think that rMB uses PXIe x2 rather than x4, but from the system info which shows NVMe, it also shows PCIe x4, which confused me.
    Now my best guess is that due to the extreme limited space available, rMB only can acommodate 2 NAND MLC flash (confirmed by iFixit, and this answers OP's question why SM951 is not an option for rMB), which is the bottleneck of the performance.
    Larger SSDs (SM951 and almost every other one on the market) have 4 or more NAND chips, which can provide greater throughput when utilized parallelly by the controller.
     
  8. unibility macrumors 6502

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    Apr 6, 2012
    #8

    I do not own a MacBook but those numbers seem pretty slow. Here's my reads from my 2015 11" Air.

    MacBook Air (11-inch, Early 2015)
    Processor Intel i7 2.2 Ghz Dual-Core
    Memory 8 GB 1600 MHz DDR3
    SSD APPLE 512 GB SSD SM0512G Media
     

    Attached Files:

  9. lcseds macrumors 6502a

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    #9
    Right. As discussed, the new Macbook does not have the speedier bus now offered in Air's and MBP's. So they are not unreasonably "slow".
     
  10. newellj macrumors 601

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    #10
    You're comparing apples to oranges. No rMB, and no pre-2015 MBA or rMBP, is going to show those numbers. They're also so far ahead of the rest of the system that they're irrelevant for most purposes.
     
  11. Meister Suspended

    Meister

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    Oct 10, 2013
    #11
    What could you guys possibly do with your macbook, that r/w speeds would make any difference?
     
  12. newellj macrumors 601

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    #12
    Or at least the difference between, say, 550 mb/s and 1100 mb/s. But even in the MBA and rMBP, no corresponding speed increases have been made for RAM or the CPU, and program code is what it is. There are a lot of speed bumps between 1100 mb/s and a noticeable real life impact.
     
  13. johngwheeler macrumors 6502

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    I come from a land down-under...
    #13
    Latency is the key metric, not throughput

    For most normal usage, it is the latency of the storage that has the biggest impact on the speed, rather than absolute throughput. Your operating system is going to access *lots* of small files nearly all of the time. The data throughput of small files, randomly accessed is way slower than the large file transfers that yield these >1GB/s transfer rates.

    The advantage of the NVMe protocol (which replaces AHCI) is that it has half the latency. This is about 2000 times faster (c. 2.8 micro-second seek times, I've read) than most magnetic disks.

    The absolute read/write speeds of SSDs only become relevant if you're doing a lot of big file transfers. The other aspects of SSD performance, normally ignored in benchmarks, are more important for most people.
     
  14. newellj macrumors 601

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    #14
    A far better explanation than I could give. :thumbup:
     

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