SLOW SSD Samsung 840 Pro

Discussion in 'OS X Yosemite (10.10)' started by yondertwins392, Oct 31, 2014.

  1. yondertwins392 macrumors member

    Joined:
    Oct 7, 2014
    #1
    Anyone experiencing slow SSD write speeds with a Samsung 840 Pro? Before I upgraded from Mavericks, I used to get 500 MB/s write speeds, now I'm getting less than 90 MB/s speeds. I've tried solutions from the following website: http://www.macissues.com/2014/10/25/how-to-speed-up-a-slow-yosemite-upgrade/
    Nothing helped. I haven't tried a fresh install, but I'm trying to avoid it. Any suggestions greatly appreciated.
     
  2. SandboxGeneral Moderator emeritus

    SandboxGeneral

    Joined:
    Sep 8, 2010
    Location:
    Orbiting a G-type Main Sequence Star
    #2
    Do you have a TRIM enabler running?

    Chameleon SSD Optimizer

    Or

    TRIM Enabler
     
  3. T'hain Esh Kelch macrumors 601

    T'hain Esh Kelch

    Joined:
    Aug 5, 2001
    Location:
    Denmark
  4. SandboxGeneral Moderator emeritus

    SandboxGeneral

    Joined:
    Sep 8, 2010
    Location:
    Orbiting a G-type Main Sequence Star
    #4
    From what I understand, and I may be wrong, SSD's don't suffer the same performance hit that a HDD does when its platters fill up to less than 10% to 15% of its capacity. SSD's should just keep on truckin' even if full.
     
  5. T'hain Esh Kelch macrumors 601

    T'hain Esh Kelch

    Joined:
    Aug 5, 2001
    Location:
    Denmark
    #5
    SSDs also slow down when getting full. (IF I understand that article correctly! :p)

    But, that 10-15% of HDD I believe is a myth, from when those 10% would be around 20GB, which is more or less what OSX uses for virtual memory in my experience. So it should be 20-30GB, which would then be 2-3% of modern drives (Assuming 1TB)
     
  6. ABC5S Suspended

    ABC5S

    Joined:
    Sep 10, 2013
    Location:
    Florida
    #6
    If TRIM is not enabled with a downloaded program moving from Maverick to Yosemite, speed will suffer and that is what OP is probably experiencing.
     
  7. yondertwins392, Oct 31, 2014
    Last edited: Oct 31, 2014

    yondertwins392 thread starter macrumors member

    Joined:
    Oct 7, 2014
    #7
    Thank you all for the responses, but I have tried enabling TRIM and it didn't work. No the drive is not full, using 51GB is left of 255G.

    After some more tests with Blackmagic, something weird is going on. It is still running slow, but there are time where it will initially read close to what it should be around 400-500 MB/s, then after each reading it will slow back own to 100-300 MB/s.
     
  8. SandboxGeneral Moderator emeritus

    SandboxGeneral

    Joined:
    Sep 8, 2010
    Location:
    Orbiting a G-type Main Sequence Star
    #8
    I know.. Thats what I asked about to him in my first post of this thread.
     
  9. SandboxGeneral Moderator emeritus

    SandboxGeneral

    Joined:
    Sep 8, 2010
    Location:
    Orbiting a G-type Main Sequence Star
    #9
    Thanks for the article link. I saved it to Instapaper and will read it later. Anandtech always has great information.

    I think you really need to work on getting TRIM running. I bet that's the reason you're experiencing the slow down.
     
  10. yondertwins392 thread starter macrumors member

    Joined:
    Oct 7, 2014
    #10
    I have tried the TRIM enabler that you suggested and it seems to have worked now. Initially it was erratic, but I guess things have settled down. Albeit there are variations between 400-500 MB/s but I can definitely live with that. So why is it that I never had this problem before the update to Mavericks?
     
  11. Weaselboy Moderator

    Weaselboy

    Staff Member

    Joined:
    Jan 23, 2005
    Location:
    California
    #11
    Now that you have TRIM up and running, do this to restore performance.

    Do a command-s boot to single user mode and type "fsck -fy" (without the quotes) at the command line. At the end of the run you will see a message about "all unused blocks TRIMed."

    Now type reboot.

    This will TRIM the free space that got cluttered up while you had TRIM off and should restore your write speeds.
     
  12. yondertwins392 thread starter macrumors member

    Joined:
    Oct 7, 2014
    #12
    Okay, just did it and seems to run much much better/faster and smoother. Thanks!
     
  13. lavrishevo macrumors 68000

    lavrishevo

    Joined:
    Jan 9, 2007
    Location:
    NJ
    #14
    Thanks. This thread was helpful in getting my 840 Pro back up to her performance levels again. This is is helpful.

     
  14. MagoX macrumors newbie

    Joined:
    Apr 18, 2015
    #15
    It works

    Update: This solution works really charmy on Yosemite.

    When upgraded to Yosemite, SSD SAMSUNG 840 PRO whent down to 90MB7s write speed.

    After activating TRIM ENABLER it did not improved immediatly, but letting it running a while, after doing fsck -fy procedure it did really work.
    Finally I'm back to 490MB/s write and 500MB/s read.

    Thanks for the post.
     
  15. SayCheese macrumors 6502a

    Joined:
    Jun 14, 2007
    Location:
    Thame, Oxfordshire, England
    #16
    Just to add to this.
    I also have a Samsung 840 Pro SSD, which was running at 90mb/s.
    I enabled the Trim in the latest OS X update and then the fsck -fy command.
    Now running around the 450mb/s

    Thanks
     
  16. sstyle macrumors regular

    Joined:
    Nov 8, 2010
    #17
    it did not help me.
     
  17. telequest macrumors regular

    Joined:
    Feb 1, 2010
    Location:
    NJ
    #18
    I'll try this on my boot SSD (Samsung 840 Pro 256GB) which is in an Apricorn Velocity Solo X1 card. But I also have been having terrible performance on my RAID 0 pair of Samsung 840 Pro 512GBs in a Sonnet Tempo SSD Pro. Is there a way to target the "fsck -fy" command to those drives? If needed, I'm prepared to wipe the drives clean (but am unclear about the best way to do that). Thanks.
     
  18. Weaselboy Moderator

    Weaselboy

    Staff Member

    Joined:
    Jan 23, 2005
    Location:
    California
    #19
    I'm sorry, but I'm not sure. I think I read that TRIM does not work over RAID drives anyway. Sorry I am not more helpful here.
     
  19. Tech198 macrumors G4

    Joined:
    Mar 21, 2011
    Location:
    Australia, Perth
    #20
  20. jbarley macrumors 68040

    jbarley

    Joined:
    Jul 1, 2006
    Location:
    Vancouver Island
    #21
    I have two SSD's in an Apple raid 0 configuration and System Report states Trim is enabled.
    Seeing as Trim is enabled I'm assuming it is also working.
     
  21. Oldmanmac macrumors 6502

    Joined:
    Mar 31, 2012
    #22
    Would this apply to Fuson drives? As they are SSD's?
     
  22. Tech198 macrumors G4

    Joined:
    Mar 21, 2011
    Location:
    Australia, Perth
    #23
    I've never managed to fill up SSD, but on my Windows box, i do see a slow performance hot when 10Gg of free space is left..

    Maybe its only a windows issue, and OS X is different...
     
  23. T'hain Esh Kelch macrumors 601

    T'hain Esh Kelch

    Joined:
    Aug 5, 2001
    Location:
    Denmark
    #24
    Absolutely not. OSX also slows to a crawl if you have less than 5GB space left, and it is noticeable below 20GB in some cases. All modern operating system rely on cached files on the hard drive to run.
     

Share This Page