Szabolcs_Dekany

Q: Abnormal read speeds on BootCamp

Hey. I've been getting extremely slow read and write speeds on some operations while using my iMac running Windows 10.

 

asd.PNG

Look at that extremely slow read and write speeds when accessing random 4KiB files. It literary takes more than two seconds just to do a refresh on the desktop. Not to mention that it also takes at least one and a half seonds just to list the drives under My computer.

 

Here's the full report of the speed test:

 

-----------------------------------------------------------------------

CrystalDiskMark 5.1.0 x64 (C) 2007-2015 hiyohiyo

                           Crystal Dew World : http://crystalmark.info/

-----------------------------------------------------------------------

* MB/s = 1,000,000 bytes/s [SATA/600 = 600,000,000 bytes/s]

* KB = 1000 bytes, KiB = 1024 bytes

 

 

   Sequential Read (Q= 32,T= 1) :   114.952 MB/s

  Sequential Write (Q= 32,T= 1) :   112.264 MB/s

  Random Read 4KiB (Q= 32,T= 1) :     1.073 MB/s [   262.0 IOPS]

Random Write 4KiB (Q= 32,T= 1) :     1.076 MB/s [   262.7 IOPS]

         Sequential Read (T= 1) :   115.971 MB/s

        Sequential Write (T= 1) :   113.034 MB/s

   Random Read 4KiB (Q= 1,T= 1) :     0.482 MB/s [   117.7 IOPS]

  Random Write 4KiB (Q= 1,T= 1) :     1.077 MB/s [   262.9 IOPS]

 

 

  Test : 1024 MiB [C: 21.3% (49.8/233.9 GiB)] (x5)  [Interval=5 sec]

  Date : 2015/12/25 20:59:07

    OS : Windows 10 Professional [10.0 Build 10586] (x64)

Anyone else having terrible speeds on their late 2015 5k iMacs?

 

Cheers,
Szabolcs

iMac, OS X El Capitan (10.11.1), Boot Camp 6.0

Posted on Dec 25, 2015 12:10 PM

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Q: Abnormal read speeds on BootCamp

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  • by Loner T,

    Loner T Loner T Dec 25, 2015 12:12 PM in response to Szabolcs_Dekany
    Level 7 (24,339 points)
    Safari
    Dec 25, 2015 12:12 PM in response to Szabolcs_Dekany

    Do you have a Fusion drive?

  • by Szabolcs_Dekany,

    Szabolcs_Dekany Szabolcs_Dekany Dec 25, 2015 12:14 PM in response to Loner T
    Level 1 (1 points)
    Dec 25, 2015 12:14 PM in response to Loner T

    Yep its a 2TB Fusion drive which, if im correct, consists of a 128GB SSD and a 2TB HDD. I assume that Windows is installed on the 2TB mechanical hard drive. Even if Apple still uses the 5400 RPM drives, this should be not happening I think.

  • by Loner T,

    Loner T Loner T Dec 25, 2015 1:30 PM in response to Szabolcs_Dekany
    Level 7 (24,339 points)
    Safari
    Dec 25, 2015 1:30 PM in response to Szabolcs_Dekany

    Run diskutil list to check. The HDDs used in these are not known for their 4K IO. You should also check fsutil fsinfo on the C: drive.

  • by darkdragondark,

    darkdragondark darkdragondark Oct 2, 2016 3:37 PM in response to Szabolcs_Dekany
    Level 1 (4 points)
    Windows Software
    Oct 2, 2016 3:37 PM in response to Szabolcs_Dekany

    Hi,

     

    Did you manage to find a solution, so far?

    I've got the same situation

     

    Capture.PNG

    I have observed that the iMac almost freeze during Visual Studio 2015 deployment.

     

    Same iMac, 5K, late 2015, 2TB fusion drive

    Yes, windows is deployed on the 2TB HDD

    (the SSD is not used at all for windows)

  • by Loner T,

    Loner T Loner T Oct 2, 2016 4:59 PM in response to darkdragondark
    Level 7 (24,339 points)
    Safari
    Oct 2, 2016 4:59 PM in response to darkdragondark

    From the Windows side, please post the output of following in an Admin CMD Window

     

    fsutil fsinfo ntfsinfo c:

  • by darkdragondark,

    darkdragondark darkdragondark Oct 2, 2016 5:54 PM in response to Loner T
    Level 1 (4 points)
    Windows Software
    Oct 2, 2016 5:54 PM in response to Loner T

    Hi,  here it is:

     

    NTFS Volume Serial Number :   0xec1013ae10137f30
    NTFS Version   :              3.1
    LFS Version  :2.0
    Number Sectors :              0x00000000778537ff
    Total Clusters :              0x000000000ef0a6ff
    Free Clusters  :              0x000000000e203843
    Total Reserved :              0x0000000000001834
    Bytes Per Sector  :           512
    Bytes Per Physical Sector :   4096
    Bytes Per Cluster :           4096
    Bytes Per FileRecord Segment  :1024
    Clusters Per FileRecord Segment  :0
    Mft Valid Data Length :       0x0000000014440000
    Mft Start Lcn  :              0x00000000000c0000
    Mft2 Start Lcn :              0x0000000000000002
    Mft Zone Start :              0x0000000000ae1e20
    Mft Zone End   :              0x0000000000aee640
    Max Device Trim Extent Count :0
    Max Device Trim Byte Count :  0x0
    Max Volume Trim Extent Count :62
    Max Volume Trim Byte Count :  0x40000000
    Resource Manager Identifier :0A22C143-88F0-11E6-ABAC-970DD1665829
  • by Loner T,

    Loner T Loner T Oct 2, 2016 6:21 PM in response to darkdragondark
    Level 7 (24,339 points)
    Safari
    Oct 2, 2016 6:21 PM in response to darkdragondark

    darkdragondark wrote:

     

     

    Bytes Per Sector  :          512
    Bytes Per Physical Sector :  4096
    Bytes Per Cluster :          4096
    Bytes Per FileRecord Segment  : 1024

    From the OS X side, can you run

     

    diskutil info / | grep "Block"

     

    Here is an example.

    diskutil info / | grep "Block"

       Device Block Size:        512 Bytes

       Allocation Block Size:    4096 Bytes

  • by darkdragondark,

    darkdragondark darkdragondark Oct 3, 2016 3:32 AM in response to Loner T
    Level 1 (4 points)
    Windows Software
    Oct 3, 2016 3:32 AM in response to Loner T

    Here is from the OS X

     

       Device Block Size:    512 Bytes
       Allocation Block Size:4096 Bytes

     

    I have looked around, it seems that this combination is for "Advanced Format (also known as 512E)" drive type.

    as detailed here: https://support.microsoft.com/en-us/kb/2510009

     

    Would it be required to convert the HDD to 4K native drive type?

    P.S. I'm new to OS X (2 weeks), although I work in IT filed for almost 20 years (mostly in software development)

  • by Loner T,

    Loner T Loner T Oct 3, 2016 4:42 AM in response to darkdragondark
    Level 7 (24,339 points)
    Safari
    Oct 3, 2016 4:42 AM in response to darkdragondark

    darkdragondark wrote:

     

    Would it be required to convert the HDD to 4K native drive type?

    Yes, if you can back up OS X and Windows, erase your internal SSD and HDD and erase/format with 4K block size, rebuild the fusion drive, restore OS X and Windows and then test.

  • by darkdragondark,

    darkdragondark darkdragondark Oct 3, 2016 4:56 AM in response to Loner T
    Level 1 (4 points)
    Windows Software
    Oct 3, 2016 4:56 AM in response to Loner T

    So in this case, the iMac came with this wrong sector format (512/4096)?

  • by Loner T,

    Loner T Loner T Oct 3, 2016 5:33 AM in response to darkdragondark
    Level 7 (24,339 points)
    Safari
    Oct 3, 2016 5:33 AM in response to darkdragondark

    darkdragondark wrote:

     

    So in this case, the iMac came with this wrong sector format (512/4096)?

    It is not 'wrong', but to quote Dylan 'The times, they are a-changin...' . Older software did not handle 4K IO, but as IO has evolved along with hardware, tests have included 4K IO testing.

     

    Human nature is to suspect low numbers with such tests as 'failures'.  If your workload does not demand large-block IO, this number is not critical. Only large video editing software and similar, benefit on a single-user Mac from 4K IO. If you want to see better numbers, you will need to make necessary changes, otherwise, unless your applications are slower, they are just numbers.

     

    Newer Macs have started using 4K on the SSD/Flash drives parts. On 2015 and later iMacs and Minis, 4K block size is common now.

     

    I suggest you test the changes thoroughly. The numbers may get better, but your normal workload IO performance is dependent on your usage patterns and applications you use.

  • by darkdragondark,

    darkdragondark darkdragondark Oct 3, 2016 7:09 AM in response to Loner T
    Level 1 (4 points)
    Windows Software
    Oct 3, 2016 7:09 AM in response to Loner T

    Well, nothing appeared as unusual to me in win10 Boot Camp, except when I have started to install Visual Sutdio 2015 (full features) and it was painfully slow.

    The installation has around 40K files and windows was frozen with the disk activity at 100% (I/O at maximum) (while max writes didn't pass 10MB).

     

    If I'm about to rebuild the Fusion drive, I'm thinking to change the HDD with a SSD, since the Win 10 Boot Camp is deployed only on the HDD part.

  • by Loner T,

    Loner T Loner T Oct 3, 2016 7:54 AM in response to darkdragondark
    Level 7 (24,339 points)
    Safari
    Oct 3, 2016 7:54 AM in response to darkdragondark

    It is possible to install Windows on the SSD part of the Fusion drive, but it requires manual partitioning and the use of diskutil cs resizeStack using a specific physical volume (PV). I will post my Mini setup which has Windows on SSD part. I only keep the core OSes on the SSD. The rest is on the HDD part.