iMac Late 2012 problem with ssd usb 3.0

Discussion in 'iMac' started by skorobuh, Mar 16, 2015.

  1. skorobuh macrumors newbie

    Joined:
    Mar 16, 2015
    #1
    Hello, first sorry for my English, is not good, but i try it.....

    I have ssd Samsung 840 PRO Series, connected by Zalman ZM-HE250 (its working only with usb cable, i don't use next usb for 5V its the same without him, i think...) its connected to my iMac by USB 3.0 and its used as primary boot disk...my system working very well as i see from first time with ssd....but is used only on system...Internal original disk is for data....I don't copy data very often sometimes some hd films, but i saw some problems with my NAS server speed by Ethernet, speed is bad between 50MB/s on my brother computer with WIN its about 90MB/s, first i changed cables, routers, switch. I buy last day new USB Flash and speed again bad, the same as by Ethernet...so i got idea try speed of disks by Black Magic Disk Speed Test, my internal disk in Mac has between 60 read and write sometimes 70-80 but it goes down, i think its not ok and my ssd is too very bad speed 80 and go down largely 60 and read is 180 max....
    problem is than i don't try anymore before how much i had from first start of my ssd, its working now more than one year, but i think there is some problem, disk has in original info 500/500. As I saw many topics here, many peoples got speed very nice from his ssd disk 400-500MB/s for read and write no problem...i try apple support and they say me try reinstall OS X but is still the same,

    Is my ssd disk ill?? or is there some problem in my configuration, when his speed is bad??

    Is possible if working speed bad by ssd too working bad on internal hdd?

    Is ok use USB 3.0 for connect boot/start disk?

    Is there some solution how to repair my disk, or is out and have to buy new one?

    Very thanks for reply
     
  2. skorobuh thread starter macrumors newbie

    Joined:
    Mar 16, 2015
    #2
    re:

    next problem is than i can't do backup of my ssd in CMD R console in disk utility, it say me after some time Error - Device not configured and my ssd is away after this error, i tryed too create dmg file of system and its wroted input/output error, I have Acronis so is last thing, what i can try....
     
  3. chogue23 macrumors member

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    Mar 16, 2015
    Location:
    Waco, TX, USA
    #3
    I think the slow downs that you are seeing is what some people call a 'bottleneck.' The term comes from a soda bottle where you have a large space in the bottom of the bottle, but it has to go through the small neck which slows everything down. USB 3.0 is your first bottleneck. USB 3 will transfer at a maximum of 5gbps or 640MBps. Remember that this is the maximum, and actual speeds will be less. If the drive was internal, it would be on a 6gbps bus and would be a little faster. The next bottleneck is the ethernet component. If you are on a gigabit ethernet it will transfer at a maximum of 125MBps theoretically, depending on the switch and cabling. This is why you are getting the slower speeds, because the data from the other machine is going from the other hard drive, to the nic card, over the cable, through the switches, and finally gets to your computer, but then it is written to the SSD boot drive in the cache and then reread by the computer. It is quite a few steps and can get complicated to think about. You can move the ssd to inside your case to remove a few steps from the process and improve the speed quite a bit, but the network will still be slower than local.
     
  4. skorobuh thread starter macrumors newbie

    Joined:
    Mar 16, 2015
    #4
    re:

    Thank you, I'm understand you, but put ssd in my mac as internal is problem...
    I can't change 1TB Data for 256GB system, when i have now 256GB+1TB
    I only don't understand why my ssd has this problem, if is it normal, than my speed is very bad and if have buy new one, if has usb 3.0 maximum 5gbits, my reduction Zalman has too 5gbits and my ssd has 500/500 why i see write speed between 80 and down, largely about 40...and read too bad, its must be some problem, when i connect to my macbook, the speed is same, so there must be problem with usb cable and its new as Zalman pack, i think there is some problem with my SSD?

    im tried yesterday do some copy of my OS X by CMD R console in disk utility from ssd and its impossible,

    Error - Device not configured and my ssd is away after this error, i tryed too create dmg file of system and its wroted

    input/output error,

    I have too Acronis, i tryed him and my mac is loading after some time and loading and everything what i can do is reboot my iMac without backup.... any idea? Thank you
     
  5. chogue23 macrumors member

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    Mar 16, 2015
    Location:
    Waco, TX, USA
    #5
    It could be that your SSD is getting full. Like a hard disk, the SSD will start to slow down as it fills up, but it is because it is looking for partially filled blocks and splitting the file into smaller pieces. This site explains it very well.

    http://www.howtogeek.com/165542/why-solid-state-drives-slow-down-as-you-fill-them-up/

    The other thing is that TRIM is not enabled by default on a non-Apple drive, so you would have to find a copy of Trim Enabler to get that working.

    As far as the rest of the post, I am not really sure what you are trying to do. If you want to copy everything from one drive to another, you would need a program like Carbon Copy Cloner. I am sorry, but the language barrier is getting in the way.
     
  6. skorobuh thread starter macrumors newbie

    Joined:
    Mar 16, 2015
    #6
    aha....

    I thought TRIM is only for internal by SATA, not for USB devices...

    I want copy my backup of ssd to internal hdd for boot from him and want put my ssd to repair service, because i think the speed is very bad and is something with him...

    so i try disk utility from console repair cmd and r

    1) There is create image....dmg..im waiting some time and error - input/output

    2) I put restore from ssd to hdd and error - device not configured - and ssd is away after this error

    3) on support on phone from apple they say me try Time Machine , i cant nothing only use window of Acronis or Time Machine and my mouse only loading, after some hours waiting still problem, is possible only shutdown iMac

    I want now only backup my ssd because want him repair
     
  7. chogue23 macrumors member

    Joined:
    Mar 16, 2015
    Location:
    Waco, TX, USA
    #7
    It is true that TRIM is only for internal drives, but you have an internal drive in an external case, so this would support TRIM. The usb that doesn't support TRIM are flash drives and other removable memory.

    As for creating a backup, OS X won't let you create a backup of your boot drive like that unless you are booted from something else. This includes the recovery partition. You would have to create a bootable flash drive with a Yosemite installer in order to create a backup. Another option would be to install Yosemite on your internal drive using a bootable flash drive, and then using the migration assistant to move all your data back over so you can get the SSD checked out.
     
  8. yjchua95 macrumors 604

    Joined:
    Apr 23, 2011
    Location:
    GVA, KUL, MEL (current), ZQN
    #8
    How wrong.

    The USB protocol itself, even with UASP, does not support TRIM. TRIM can only be enabled over PCIe (including Thunderbolt) and SATA.

    For instance, my internal Apple SM256E (from an Ivy Bridge rMBP) in a Transcend USB 3 enclosure with UASP cannot have TRIM enabled, simply because it's USB. If I attach it in a mSATA-Thunderbolt adaptor, TRIM can be enabled.
     
  9. chogue23 macrumors member

    Joined:
    Mar 16, 2015
    Location:
    Waco, TX, USA
    #9
    Thanks for the clarification, my apologies for the mistake.
     
  10. skorobuh, Mar 18, 2015
    Last edited: Mar 18, 2015

    skorobuh thread starter macrumors newbie

    Joined:
    Mar 16, 2015
    #10
    still problems!

    As i wroted i try Disk utility from console repair - CMD + R

    1) Checksum of disk - error - device not configured - and ssd is away after this error

    2) I try create image....dmg..Im waiting some time and there is error - input/output

    3) I try restore from ssd to internal hdd and error - device not configured - and ssd is away after this error

    4) I try Acronis in system and after some time , dock not working, i can't nothing, only use window of Acronis, ...and my mouse only loading and loading, after some hours waiting still problem..... only one possible is shutdown my mac from button

    5) I try Time Machine in system, after some time, too computer loading and loading on mouse, sometimes is rebooted automatically, because iMac has white screen, there is error
    my SSD has 200GB used...music, photos, documents...i put my others data to external disk, but there was problem in Parallels image of my Win7 he can't copy to my external disk and my system restarted automatically, so i delete him....i have now SSD with 80GB used, but there is still some problem with something because points from 1 to 5 do problem

    yesterday i got only one possible Time machine backup but it was only 100GB from 200GB, many things wasn't same as on SSD, there wasn't file from parallels image and more things wasn't there, so not good backup, today only problems

    - I try both - copy to internal hdd or next external hdd and this problems are still there, so I think there is problem with SSD

    I try install new system, used as started system, again CMD + R and points 1-5 problems again

    So this not working!!!!

    I try install new system and do there migration...but all applications are out?
     

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