Macbook Pro Intel 520 SSD Slow Read/Write Windows 7

Discussion in 'MacBook Pro' started by sinterklaas1212, Apr 13, 2012.

  1. sinterklaas1212, Apr 13, 2012
    Last edited: Apr 13, 2012

    sinterklaas1212 macrumors newbie

    Apr 13, 2012
    Yesterday I placed an Intel 520 SSD in my Macbook Pro early 2011 edition. I removed the old hard disk and placed in the ssd, and installed windows 7 on it, without having OS X Lion installed. Even though my SSD performs admirably, it still seems like it's underperforming by around 200 MB/s for both read and write. I used the ATTO disk benchmark and at a transfer size of 128Kb, does it start listing speeds of around 290MB/s for read and 335MB/s for write. I looked around for enabling AHCI but this prevents the computer from being able to go to sleep, and I don't want this. Am I missing something? I installed the Intel Toolbox already and everything seems fine there. The SSD is running in IDE mode right now. I also installed all the drivers from bootcamp 4.0.

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  2. sinterklaas1212 thread starter macrumors newbie

    Apr 13, 2012
  3. r1dePrkCty macrumors newbie

    Jun 14, 2009
    Hey, if you still haven't figured this out it is because macs cannot run in AHCI Mode when using windows. If you ran OSX using this drive you would see normal 500 MB/s speeds but under windows you lose sata III performance and it essentially drops to SATA II without AHCI
  4. shortcut3d macrumors 65816

    Aug 24, 2011
    You can enable AHCI if you feel it's important for the speed. It helps with random read/writes just as much as raw throughput. Here is the most cited link to enable it:

    You will sacrifice sleep/standby/hibernate because Windows 7 can read AHCI settings from the EFI.

    You could also attempt to install Windows natively using EFI and GUID partition.
  5. ixodes macrumors 601


    Jan 11, 2012
    Pacific Coast, USA
    I tried Intel, OCZ, and finally settled on a Samsung 830 Series for mine. Unlike Windows 7 on my ThinkPads which are very fast with either an Intel or OCZ, OS X is best suited to an 830 series for optimum performance.
  6. shortcut3d macrumors 65816

    Aug 24, 2011
    I'm not sure what you are referring to, but my testing with SF-2281 and Samsung 830 SSDs perform the same in my 2011 Macs as a Lenovo X220. The performance in OSX does not need any tweaks. The SF-2281 and Samsung 830 SSDs both have excellent garbage collection. You may get unintented negative consequences if you use the TRIM hack in OSX. To get equivalent performance in Windows, one would need to apply the AHCI hack or install Windows in native EFI.

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