Update: It appears this may be a function of the 1TB drives fitted to both 13- and 15-inch models. The reason for this isn’t yet clear: it may be the drives used offer greater bandwidth.

Benchmark tests by French site Mac4Ever show that the latest MacBook Pro 15 is delivering SSD read and write speeds in excess of 1GB per second. The site repeatedly achieved these speeds when Apple claims only “up to 775MB per second.”

The MBP 15 is able to achieve these speeds because it has a 4-channel PCIe connection to the SSD, in contrast to the 2-channel link on the MBP 13 and MacBook Air models, though from some reader reports this may be the case only on models fitted with 1TB drives …

PCIe is a high-speed serial link used only on the latest Macs, replacing the slower SATA connections of earlier machines. SATA 3 is good for around 600MB/sec, which was more than fast enough for hard drives but not capable of keeping up with the speeds of modern SSDs. PCIe 3.0  is capable of a theoretical maximum of 8GB/sec, allowing plenty of spare capacity for faster future generations of SSD.

Per lane (each direction):

  • v1.x: 250 MB/s (2.5 GT/s)
  • v2.x: 500 MB/s (5 GT/s)
  • v3.0: 985 MB/s (8 GT/s)
  • v4.0: 1969 MB/s (16 GT/s)

So, a 16-lane slot (each direction):

  • v1.x: 4 GB/s (40 GT/s)
  • v2.x: 8 GB/s (80 GT/s)
  • v3.0: 15.75 GB/s (128 GT/s)
  • v4.0: 31.51 GB/s (256 GT/s)

It seems likely that Apple was keeping things simple by citing the performance available across the range rather than noting the far higher speed of the top-of-the-range model.

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11 Responses to “Latest MacBook Pro 15 gets blazing SSD performance thanks to 4-channel PCIe (updated)”

  1. WANG Mengke says:

    Hey, could you test the 4K performances? Serial reading/writing speeds are not so useful for daily tasks.


    • Kris404 says:

      Why would you get a top-of-the-line 1TB 15″ rMBP for ‘daily tasks’?

      Sequential read/write is very useful for large files such as video. I’m not discounting 4K/32K performance but high sequential I/O is useful for other tasks.


  2. Tim Jr. says:

    Nice! I have the 1GB version.. though I got it for space, not speed. nice to know I got a blazing fast SSD. :D


  3. How to measure the 4K speeds ? I got the 1TB version ;)


  4. Kris404 says:

    Amazing I/O for a non-RAID laptop.


  5. Alex says:

    My MacBook Pro 2013/1TB handles four streams of 4K well – http://blog.alex4d.com/2013/10/31/4-uhd-streams-on-a-mac/


  6. I have a late 2013 13″ Macbook Pro with 1TB of PCIe flash storage. When I run Black Magic Disk Speed Test, I receive results of 1013.1 MB/s write and 892.1 MB/s reads. This is much faster than the 512GB version which I returned for the larger storage.


  7. Ze'ev Gilad says:

    can anyone comment on the 2014 models? are the 512 and 1024 the same speed?