Looks like no one’s replied in a while. To start the conversation again, simply ask a new question.

User profile for user: theposco
theposco Author
User level: Level 1
1 points

Should I send my Samsung Evo 840 SSD back?

It has been brought to my attention on here that the Samsung Evo 840 SSDs have a design flaw. Apparently the read times start to slow down! I have two of them, both 1TB. One I have had for almost a year and the other one I received just the other day.


I can't run a speed test on the first one (oldest) as it is my boot drive and Black Magic Disk Speed Test can't access it due to it being read only apparently. The other 1TB SSD I am using as a drive to store, access and edit photos. I did run a test on that drive and all appeared to be fine, but I have now just read that testing the drive can hurt it!!


So two questions;


1. Is it right that I shouldn't run a speed test on an SSD?

2. How can I test the boot drive to make sure the read performance is as it should be?


The computer starts up pretty fast - 35 seconds to the login screen.


Thanks.

Posted on May 30, 2015 2:16 PM

Reply
23 replies
User profile for user: Kappy
Kappy
User level: Level 10
361,741 points

May 30, 2015 2:25 PM in response to theposco

1. Be judicious as writing needlessly to an SSD will shorten its life, although not by much unless all you do is benchmark and test.

2. Boot from another drive or simply stop worrying over it. After all it's working as well as the other one.


Do you know what the design flaw is and if it affects your drives or ever will affect them? That model has undergone extensive reliability testing and found to be more reliable than five other competing SSD brands and models.

Reply
User profile for user: Grant Bennet-Alder
Grant Bennet-Alder
User level: Level 10
127,183 points

May 30, 2015 2:27 PM in response to theposco

Apparently the read times start to slow down!

That is true of ANY third-party SSD, as it begins to become clogged with deleted data.


Mac OS X is designed for Rotating drives that pre-allocate and pre-number every block. When a data in a block is deleted, that block is added to the free list and it will be re-used.


Not so with a third-party SSD. Blocks are allocated dynamically, and unless TRIM or some other scheme is applied, deleted blocks accumulate and the drive slows down. If you run a speed test on an SSD, it will create many blocks that will further clog it up. After you run a speed test, you should erase the drive, thus changing the results of the speed test.


Better than a speed test is understanding how this works:


http://en.wikipedia.org/wiki/Trim_(computing)


.

Reply
User profile for user: The hatter
The hatter
User level: Level 9
60,990 points

May 30, 2015 2:34 PM in response to theposco

Firmware current?


TRIM enabled?


You should always have a bootable 2nd system drive. From there you can run DU which will "trim un-needed blocks" for one thing.


SSDs have been torture tested to over 500TBs of writes with marginal small % slowdown if any. Without TRIM they will.


And SSDs evolve and improve - nothing I have seen has changed so much in just the years since August 2008 when p0eople began using one in Mac Pro, such as the XP941 last year, the SM951 this year.


Never "secure erase" an SSD (DU won't let you). but do be ready to repartition and restore (with TRIM enabled on the source). And if running Yosemite you hae to decide what to do.


Some of the OEM Samsung/Apple PCIe-SSD "'blades" because they report themselves as Apple TRIM gets automatically enabled. This to me is one of the dumbest tricks - preventing retail devices on a modern OS from using technology that helps the life of and needs to be enabled in the OS and is part of the specifications for all SSDs bar none. TRIM that sail, sailor!

Reply
User profile for user: lllaass
lllaass
User level: Level 10
210,411 points

May 30, 2015 2:59 PM in response to theposco

In Finder click on Get Info for the startup disk.

Check the Sharing an& Permissions to make sure it says Read and Write.

I had same problem until I fixed the Sharing & Permissions to allow both read and write.

theposco wrote:


Thanks, but I have already tried that tool:


"I can't run a speed test on the first one (oldest) as it is my boot drive and Black Magic Disk Speed Test can't access it due to it being read only apparently."

Reply
User profile for user: theposco
theposco Author
User level: Level 1
1 points

May 30, 2015 3:22 PM in response to The hatter

I wasn't aware that I even needed to deal with any firware for the SSD and I wouldn't know the method of how to check it or update it.


I had a look on youtube (I learn better from videos) for TRIM and one guy said to go to Groths.org/trim-enabler to download a utility to enable TRIM. I'm a bit wary of going to random sites though and also enabling things I don't understand. Is there a site you would say is trusted for enabling TRIM and do I have to update the firmware first? I don't know how to update the firmware by the way.


"You should always have a bootable 2nd system drive. From there you can run DU which will "trim un-needed blocks" for one thing."


"Never "secure erase" an SSD (DU won't let you). but do be ready to repartition and restore (with TRIM enabled on the source). And if running Yosemite you have to decide what to do."


I don't fully understand the above two statements. Like how to trim un-needed blocks. I know what a partition is and what secure erase is, but not the rest. Sorry, a bit limited on techie knowledge.

Reply
User profile for user: theposco
theposco Author
User level: Level 1
1 points

May 30, 2015 3:25 PM in response to Kappy

Kappy wrote:


Do you know what the design flaw is and if it affects your drives or ever will affect them? That model has undergone extensive reliability testing and found to be more reliable than five other competing SSD brands and models.

Here is one place I saw talking about a problem: http://www.extremetech.com/computing/199673-second-patch-for-ongoing-840-evo-ssd -performance-issues-being-prepped-by-sam…

Reply
User profile for user: Grant Bennet-Alder
Grant Bennet-Alder
User level: Level 10
127,183 points

May 30, 2015 4:34 PM in response to theposco

There is more than enough high-powered technical discussions of SSD drives and their legitimate technical issues issues available online. Much of it is from reputable sources such as Anandtech and Ars Technica, and similar sources with good reputations.


You should not be paying the slightest attention to ANYTHING posted on YouTube for accurate SSD information.

Reply
User profile for user: theposco
theposco Author
User level: Level 1
1 points

May 31, 2015 3:05 AM in response to Grant Bennet-Alder

Grant Bennet-Alder wrote:


There is more than enough high-powered technical discussions of SSD drives and their legitimate technical issues issues available online. Much of it is from reputable sources such as Anandtech and Ars Technica, and similar sources with good reputations.


You should not be paying the slightest attention to ANYTHING posted on YouTube for accurate SSD information.

Ok that's fair enough, but I have to start somewhere and how am I supposed to know which information is correct and which is not unless I give you an example of some information for you to say whether it is right or not?


I probably wasn't very clear in my last post, but I was really interested in seeing if the TRIM enabler source he used for his video was reputable and correct, not so much whether HE could be trusted. I mentioned he said it could screw your system because he was giving a backgound to the TRIM enabler software before Yosemite came out. The TRIM enabler software worked just fine until Yosemite came with security measures that then required the TRIM enabler software to be updated so people didn't get a grey screen on reboot.

Reply
User profile for user: theposco
theposco Author
User level: Level 1
1 points

May 31, 2015 3:43 AM in response to The hatter

The hatter wrote:


You should always have a bootable 2nd system drive. From there you can run DU which will "trim un-needed blocks" for one thing.


Never "secure erase" an SSD (DU won't let you). but do be ready to repartition and restore (with TRIM enabled on the source). And if running Yosemite you have to decide what to do.


Some of the OEM Samsung/Apple PCIe-SSD "'blades" because they report themselves as Apple TRIM gets automatically enabled. This to me is one of the dumbest tricks - preventing retail devices on a modern OS from using technology that helps the life of and needs to be enabled in the OS and is part of the specifications for all SSDs bar none. TRIM that sail, sailor!


Ok, I have a Lacie USB external HDD, could that be used as my second bootable drive (let's call it Boot B)? So I could use that to fix Boot A (my current bootable SSD drive with all my files etc) whilst it is offline. And Boot B would not need to have all my software and files etc, just a copy of Yosemite simply to access Disk Utility to fix Boot A? How do I use Disk Utility to "trim un-needed blocks" on Boot A?


I don't understand what ypou mean when you say "TRIM gets automatically enabled" on "OEM Samsung/Apple PCIe-SSD blades" and then go on to say what sounds like TRIM isn't being enabled and should be?

Reply
User profile for user: theposco
theposco Author
User level: Level 1
1 points

May 31, 2015 5:45 AM in response to The hatter

The hatter wrote:


Clone your system - http://www.bombich.com


Install TRIM Enabler

https://www.cindori.org/software/trimenabler/

http://www.macupdate.com/app/mac/37852/trim-enabler


Run Disk Utility => Repair Disk

Sorry to keep asking question, but I want to make sure I know what I am getting myself into here.


I can indeed install TRIM enabler, but what's to stop Apple making another change at the next OS update and then the TRIM enabler doesn't work and I am found sat in front of a grey screen with a stop sign?


Should I enable it for now and then turn it off before any update until I am sure the patch will work with the new OS update? It sounds a bit messy having to use a patch that will only work for an indefinite length of time and one that is not supportd by Apple.

Reply

Should I send my Samsung Evo 840 SSD back?

Welcome to Apple Support Community
A forum where Apple customers help each other with their products. Get started with your Apple ID.
Learn more Sign up