SOLVED Hard drive transfer speeds suddenly slower than normal

Discussion in 'Troubleshooting Help' started by Potplanty, Sep 6, 2017.

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  1. Potplanty

    Potplanty Member

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    Hey all,

    Weird issue with my HDDs transfer speeds slowing down a lot. I just recently started using AOMEI Backupper Pro but found the program itself was absolute crap (told it to backup F: drive, it'd backup H: drive instead, memory leaks when verifying backups etc). While backing up I noticed the speed was consistent with normal Windows file transfers of ~140-160MB/s. During this period I got halfway through some backups before it would lock up my computer entirely and force me to reset it. I also cancelled a few backups part way through as it wasn't doing what I told it to.

    I then got EaseUS ToDo Backup and used that (great program btw) but noticed the speeds were ~40-50MB/s, about three times slower than with AOMEI. I went back to AOMEI to test it again with their software and it was also showing that speeds were now 40-50MB/s. Then I tried copying files with Explorer and that was also about the same. Only mentioning the programs in case one of them maybe changed a setting or the hard locks of my computer may have triggered something.

    I've checked the controllers in devmgmt and all of them are showing as running in Ultra DMA6 mode. All drives are running on SATA3 ports w/ the proper cables in AHCI mode. The speeds were consistent across all my drives (2x Seagate ST4000TN000 and 4x Seagate ST4000VN008) and none of them have any SMART errors (the 4x VN008 models are almost brand new). Now I've checked everything I can think of and I can't figure out why the computer would suddenly drop the speeds of all drives like this. Backups are now taking ~16-20 hours rather than the 8 hours it was before.

    All help appreciated.

    tl;dr drives were backing up @ ~150MB/s, suddenly all drives slowed to ~40MB/s across the board.
     
    Last edited: Oct 5, 2017
  2. terrastrife

    terrastrife Member

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    full drive = slow, empty drive = fast.
     
  3. FOTW

    FOTW Member

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    Use HDtune Pro trial version to test and benchmark the HDDs, you can also run a health check and sector scan, in case the SMART data hasnt picked it up yet.

    If your running RAID and one of the HDDs is failing your read/write speeds across all the raided HDDS will be affected.

    As mentioned more data on HDD the slower it gets, also it can depend on source HDD read speeds. if source HDD is failing or near capacity your speeds will slow down.


    Also the type of data being transferred can have a effect so if your transferring lots of files that are on different sides of the platter things can slow down quite a bit.
     
    Last edited: Sep 6, 2017
  4. Bold Eagle

    Bold Eagle Member

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    With the back up programs did you ensure to remove them completely using CCleaner and it's registry cleaner to make sure either of the programs weren't trying to 'control the copying process' causing conflict with your host controllers (disk controller).
     
  5. OP
    OP
    Potplanty

    Potplanty Member

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    Makes sense. All have <5% free so fair enough.

    No RAID, only single disks. Fragmentation is also at 0% for all drives.

    I didn't even uninstall AOMEI tbh but I've done it now and I'll give it a shot.
     
  6. OP
    OP
    Potplanty

    Potplanty Member

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    It's at the point now where transferring files between two drives is going at ~10MB/s maximum (several files, couple hundred MB at most). Both drives are on about 8% space available, both running SATA3, AHCI mode in BIOS. This is after a fresh install of Win10 (was on 7 at the time of original post) so I'm dumbfounded. I've run Winsat on all drives and the sequential read/write speeds are fine while the random is pretty abysmal (see below). Completely at a loss now and about to say the controllers are screwed and I should upgrade my mobo.

    > Disk Random 16.0 Read 1.64 MB/s 4.1
    > Disk Sequential 64.0 Read 165.83 MB/s 7.2
    > Disk Sequential 64.0 Write 147.44 MB/s 7.1
    > Average Read Time with Sequential Writes 5.631 ms 5.8
    > Latency: 95th Percentile 20.266 ms 4.6
    > Latency: Maximum 222.598 ms 7.3
    > Average Read Time with Random Writes 8.124 ms 4.9
     
  7. cvidler

    cvidler Member

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    No it doesn't.

    It MAY happen on a full SSD, but only for writing (where it has to erase a page before writing, rather than just writing to an already blank page), not reading.
    Regular spinning rust HDDs, have no care for fullness.

    You may encounter slowness at the file system level due to fragmentation, but you've said there's 0% fragmentation, so that's not it.


    What I'd be looking at, is maybe conflicting VSS drivers for both of those back up tools.
     
  8. OP
    OP
    Potplanty

    Potplanty Member

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    Alright well that's ruled out then. I just did a fresh install of Win10 yesterday and between two drives it won't go faster than 10MB/s (several files of several hundred MB each) even without the backup software (using Ctrl-C + Ctrl-V) so I think I can rule out VSS drivers conflicting.
     
  9. terrastrife

    terrastrife Member

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    HDD with less than 5% space which means it's probably fragmented and the only free continuous space is at the end of the disk, the slowest part.

    A commen example is a HDD may get about 240MB/sec at the start but only 100MB/sec at the end, add in any fraction of second of seeking (due to fragmentation) and the speed tanks even further.

    Synthetic read tests are still going to show full speed as they're only reading existing data, however, a write test will need to write data where it can, and with 5% free space it's going to be everywhere, hence slow speeds.

    Although those results do show that there's maybe something broken with NCQ.
     
  10. OP
    OP
    Potplanty

    Potplanty Member

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    I just ran a defrag again on Windows 10 (which is apparently a lot smarter when it comes to such matters) and some of my drives were fragmented up to 35%. So I'm defragging them now (up to 10 passes some of them took) and I'll see what happens after.
     
  11. Bold Eagle

    Bold Eagle Member

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    ^^agree with this.

    Letting disks fill up that far is your issue. Have a look at a Defrag of HDD's and you can note the coloured clusters are throughout the HDD at the start and then more organised at the end.

    Does one of them have your OS on it (with <5% how will it ever be able to update OS?).
     
  12. merlin13

    merlin13 Member

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    Historically seen anything less than 20% free will cause WinDoze to start to Cough Fart Splutter with drive access speeds.

    But been noticing odd drive stuttering/video playback buffering/Cough Fart Splutter after a WinDoze 7 Update a few months ago on an i5 Win 7 64 bit machine here... 6 gig RAM and less than 40% used on a 300 gig spinner well defrag'd as well.

    Mind you, if they get three red lights in a row on the road people generally blame an Update, so...
     
  13. OP
    OP
    Potplanty

    Potplanty Member

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    The disks are all for media files and nothing else. May as well use all the space I paid for.

    The issue is that the disks I'm writing to are empty. Not a single byte used. The source disks are the full ones and even then, the read speed shouldn't be as bad as 10MB/s regardless.

    OS is on a separate SSD.
     
  14. Bold Eagle

    Bold Eagle Member

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    Last edited: Sep 19, 2017
  15. OP
    OP
    Potplanty

    Potplanty Member

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    Deleted a lot of files I can download in smaller sizes and formats. Seems that one of my drives is actually backing up now (it would lock up earlier) with ~10% free (versus the 5 or so before). Another drive is going a lot faster than it was too so thanks for that.

    On that note, would you believe I saved 108GB alone by deleting a backup of Rainbow Six Siege? Ubisoft have no idea what they're doing it would seem because the entire game is ~600 files.
     
  16. OP
    OP
    Potplanty

    Potplanty Member

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    Okay. It took me a month or so but I finally figured out the issue and it has absolutely nothing to do with how full the drive is.

    When I performed a backup of my drive using EaseUS for the first time I happened to cancel it midway for some reason or another. Upon going to backup again properly I ran a quick format of the drive just to have a (sort of) clean slate to work with.

    Turns out that the backup that was created originally (before the quick format) was still being accessed by EaseUS and written to (even though the entire index was missing) WHILE it also wrote to the new backup file that was on the new index. Windows could not see this old file since it wasn't indexed but it was definitely there. I know this because when the new backup file was in existence Windows was reporting that double the space of the backup was being used.

    All-in-all, backups are back to 180MB/s and everything is looking good. Turns out it was going at <50MB/s because it was writing two copies at once to different sectors of the disk. Thanks for everyone that helped.
     
  17. FOTW

    FOTW Member

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    :thumbup: Cheers for letting us know
     
  18. terroristone

    terroristone Member

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    Thanks for letting us know you have found the issue, many threads left un answered here. I check my disk usage from time to time as i have found a few programs doing weird shit, which isnt good on a ssd.

    T1
     
  19. HobartTas

    HobartTas Member

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    If you want to simulate your effect of low speeds then all you have to do is start copying say a large file (couple gigs) in folder A to folder B and you will get anywhere from 50MB's to 100MB's in simultaneous reading and writing but if you then start copying another file also say a couple gigs in size from say folder C to folder D then windows starts interleaving all four actions and uses small chunks of data and hence you do collapse down to something close to the 1.64MB's random disk access for 4KB blocks you get for your hard drive however windows probably uses something larger like say perhaps 64KB chunks so you effectively get total transfer rates of single digit MB's.

    I'm kind of surprised you haven't really noticed this because if any of my hard drives start doing this you can hear them as they sound a bit like washing machines on spin cycle and the computer box vibrates slightly.

    This is one of the reasons that SSD's have become very popular because although their sequential speeds have increased to anywhere from 500-2000 MB's from hard drives 150-200 MB's their random 4K access speeds are spectacular and usually 40-50 MB's for a queue depth of 1 and for larger queue depths of say 64 can be around the 300 MB's which is way higher than the measly 1.64 MB's your hard drive gets so for business purposes that need a lot of IOPS they are a godsend no matter how expensive they are.
     
  20. OP
    OP
    Potplanty

    Potplanty Member

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    The disks are only used as weekly backups and other than that are just cold storage so it's not something I'd see unless I was actively performing the backup. On top of that they're decent drives and I've got a good case that mounts them nice and securely.
     

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