I installed to my Imac late 2012, a ssd Samsung Evo 850, replacing the original HDD. With the new version of Yosemite 10.10.4 is suitable to enable Trim ?

This is not an answer, but I need help.

Are you using a 21.5" iMac or the 27" iMac. If 21.5, have you had any issues with the SSD? When you use BlackMagic Disk Speed Test,, how fast is the speed?

My 850 EVO fails to be recognised half the time I boot my iMac up.

10.10.4 can have Trim installed. To do so open Terminal and enter:

Sudo trim force enable

and follow the on-screen prompts.

To verify Trim has been enabled, open System Information - Sata/Sata Express - select the SSD and look to the right for Trim Support. If it says Yes it is working.

I have not independently verified them, but there are warnings circulating that the TRIM function of Samsung 8xx series can cause disk corruption on Macs (by zeroing the wrong portions of the storage).

That is a standard warning, you can ignore it.

Just to be clear, I'm not referring to the standard "Apple hasn't tested it" warning, but to specific diagnoses of problems on *nix-based systems.

I was referring to the Apple Standard warning. I don't use a Samsung SSD so I don't peruse those forums. Your SSD, so the decision is up to you.

Apple does not support trim on third party SSDs, so if you enable it, you may - or may not - have unexpected results. Personally, I have an SSD from OWC and they have advised not to use it on theirs, so I will not as long as the SSD is covered by their warranty as it'll be their nickel if something goes wrong with it.

babowa wrote:

Apple does not support trim on third party SSDs, so if you enable it, you may - or may not - have unexpected results. Personally, I have an SSD from OWC and they have advised not to use it on theirs, so I will not as long as the SSD is covered by their warranty as it'll be their nickel if something goes wrong with it.

Beginning with 10.10.4 Apple kind of began supporting third party SSDs. I have 2 Macs (1 iMac and 1 MM) with OWC SSDs that using 10.10.4 and used the

Sudo trim force enable command on successfully. This is outlined in many articles including:

http://www.macissues.com/2015/07/01/how-to-enable-trim-on-third-party-ssds-in-os -x/#more-3589

Yes, thanks, I saw that - however, I've also read quite a few discussions on this "kind of support" (both pro and con) and because it's an OWC SSD with Sandforce and they told me not to, I won't do it and, until it is better "integrated" and/or one does not need a terminal hack command.

babowa wrote:

Yes, thanks, I saw that - however, I've also read quite a few discussions on this "kind of support" (both pro and con) and because it's an OWC SSD with Sandforce and they told me not to, I won't do it and, until it is better "integrated" and/or one does not need a terminal hack command.

Totally understand. I have had Trim installed since 10.10.4 was released, so far both computers are running extremely well.

The Samsung SSDs 400 500 EVO and EVO Pro have design faults: data loss. And a Fault in the controller that makes Trim even more dangerous as normal.

Samsung knows these failures already for more than half a year, until now they did not succeed to make a FirmwareUpdate available. They expect to have it in the near future, but it will not correct the failures: it will refresh all data every 3-6 months to avoid the data loss, it will slow down the disk and Trim will stay as dangerous as before. I would return the SSD and buy another brand (also without installing Trim).

I send you 1 of dozens articles about the issues in these drives, with enough side information about Trim to rethink installing it,

the title is not very aarming, but read the article to the end:

http://www.extremetech.com/gaming/203449-new-samsung-840-evo-firmware-will-add-p eriodic-refresh-capability

Lex

What happened when I don't turn trim with terminal on 10.10.4? it should works slower but slower than hdd? And any other problems?