Clean Install Yosemite onto new SSD (Also, what is TRIM?)

My issue was also a bad SATA cable internally. My samsung 850 EVO 250GB worked fine externally thru SATA-USB cable.And I also got all possible errors when having the SSD inside the macbook, couldnt unmount, partition/erase and so on. So I finally went thru with the SATA cable switch. And then it worked!

Thanks Sorciuch,

I followed your instructions and the install went flawlessly on my late 2011 15" MBP. Really easy to do. I used an EVO850 SSD. I also upgraded the RAM with from 4GB to 16GB.

The performance difference is unreal. Maybe this will finally make me deal with all those duplicate iTunes files.... well someday.

sorciuch wrote:

Well, I found out what TRIM is - allows an OS to inform a SD which blocks of data are no longer considered in use and can be wiped/overwritten. And it looks like Apple took away support of TRIM enabled third party SSDs for Yosemite. So it looks like I'll need to find an SSD with TRIM already on it which is supported by Apple.

You won't have to find "an SSD with TRIM already on it which is supported by Apple" any more.

As of Yosemite 10.10.4, TRIM is now supported using a Terminal command.

In Terminal you'll enter:

sudo trimforce enable

Enter your Password and you'll see this:

IMPORTANT NOTICE: This tool force-enables TRIM for all relevant attached

devices, even though such devices may not have been validated for data

integrity while using TRIM. Use of this tool to enable TRIM may result in

unintended data loss or data corruption. It should not be used in a commercial

operating environment or with important data. Before using this tool, you

should back up all of your data and regularly back up data while TRIM is

enabled. This tool is provided on an “as is” basis. APPLE MAKES NO WARRANTIES,

EXPRESS OR IMPLIED, INCLUDING WITHOUT LIMITATION THE IMPLIED WARRANTIES OF

NON-INFRINGEMENT, MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE,

REGARDING THIS TOOL OR ITS USE ALONE OR IN COMBINATION WITH YOUR DEVICES,

SYSTEMS, OR SERVICES. BY USING THIS TOOL TO ENABLE TRIM, YOU AGREE THAT, TO THE

EXTENT PERMITTED BY APPLICABLE LAW, USE OF THE TOOL IS AT YOUR SOLE RISK AND

THAT THE ENTIRE RISK AS TO SATISFACTORY QUALITY, PERFORMANCE, ACCURACY AND

EFFORT IS WITH YOU.

Are you sure you wish to proceed (y/N)? y

Your system will immediately reboot when this is complete.

Is this OK (y/N)? y

Enabling TRIM...

.

.

Operation succeeded. Your system will reboot momentarily, please wait...

Lex

Could I get your opinion on this article below? Specifically it was why I went with OWC's Mercury Electra SSD.....Also because of the lengthy scary disclaimer that FatMac just posted when inserting trim into Yosemite 🙂

http://www.imore.com/os-x-10104-and-trim-support-should-you-turn-it

From the article the pertinent parts about trim support and why it is unnecessary in OWC's SSD's

"If you bought your Mac with an SSD factory-installed by Apple, you don't have to worry. First party SSDs do their own garbage collection, so no changes are necessary for those systems. Third-party SSDs equipped with SandForce controllers, like the ones sold by Other World Computing (OWC), you don't need any help either"..... "The problem is that not all SSDs implement trim support the same way, and some models from some manufacturers appear to have very buggy trim implementations all together."

As you had mentioned, it brings up potential security issues (disrobing security layers) when trying to implement trim commands on Yosemite, so I decided to go with OWC which has a reputation of not falling off in speed/performance over time like other SSD's and for which trim is also unnecessary.

Thanks in advance for any assistance

Jeremy

darkroomboy wrote:

...From the article the pertinent parts about trim support and why it is unnecessary in OWC's SSD's

"If you bought your Mac with an SSD factory-installed by Apple, you don't have to worry. First party SSDs do their own garbage collection, so no changes are necessary for those systems. Third-party SSDs equipped with SandForce controllers, like the ones sold by Other World Computing (OWC), you don't need any help either"..... "The problem is that not all SSDs implement trim support the same way, and some models from some manufacturers appear to have very buggy trim implementations all together."...

Having just read that article, it's remarkable how many errors it contains.

E.g., "First party SSDs do their own garbage collection, so no changes are necessary for those systems." First party (i.e. Apple) SSD's don't need "changes" because Apple has already enabled TRIM for them.

Another example: TRIM doesn't replace Garbage Collection, it assists it. See this discussion for how they work together. Note especially that most of the explanation comes from the company which developed the SandForce controller, which is what OWC uses. This more SandForce related discussion gets into more detail about how SandForce can sort of make do if TRIM isn't easily available (as it wasn't in the days before TRIM Enabler) and is from the new owner of SandForce.

As far as the scary disclaimer goes, that's what you see when you start to invoke trimforce in Terminal. There have been reports of difficulties with Samsung SSD's, and the user takes on the burden of any ill effects, not Apple, once you accept the disclaimer.

Great advice on the install procedure. I'm about to do it. May I ask, why do I need to partition it and what is the GUID partition?

thanks

you need to partition new drive because new drive came without partitions

GUID partition is type of partition that works with Mac 🙂

BUt what about if I don't want a partition? I just want my 500gb ssd to be one drive, not partitioned into 2.

If you don't want to partition the SSD then you will have to use a Windows emulator, such as Parallels, to run Windows.

Hi All,

I will be attempting an SSD in my wife's white pre-unibody mac 2009. I plan to boot to a firewire disk with 10.7 and then do the install on the internal new SSD. It's a Samsung 850 EVO 250gb. I really miss Firewire in the new apple portables. It was so nice to boot to an external FW drive and then install on the new internal disk. Those days are gone...

chivo243 wrote:

Hi All,

I really miss Firewire in the new apple portables. It was so nice to boot to an external FW drive and then install on the new internal disk. Those days are gone...

I just purchased a new MBP. Since I have a number of TireWire accessories, I also purchased a ThunderBolt to FireWire adapter so that I could continue using them. It works like a champ.

http://www.apple.com/shop/product/MD464LL/A/apple-thunderbolt-to-firewire-adapte r

You can also get thunderbolt drives.

http://www.apple.com/shop/question/answers/readonly/start-up-drive-via-thunderbo lt/Q2PFYTDY4T2HCYAAK?tagName=mac