Model A1311 / Mid 2011 / 2.5 & 2.7 GHz Core i5 or 2.8 GHz Core i7 Processor

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iMac 21.5" mid 2011. SSD installation

Hello. I have a 21.5" mid 2011 iMac with a conventional hard disk that has an awful performance. Before looking for a whole new computer, I'd like to try a SSD install. Not as a second unit. Just remove the actual one and install a SSD one.

I found a guide to change the hard disk, so I hope steps are similar.

What should I get for that change?

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I finally did it this weekend. I finally did the change from hard disk to ssd instead of adding it as a second drive.

I got the kit Dan linked me and the most tricky part was dealing with the magnets when mounting the screws again and adapting the 2.5 to 3.5 case, as it was smaller than the hard disk

I also bought 2x4GB DDR modules and now, with both the SSD and the 12GB of RAM, mi iMac is running as it never did! In performance terms is like having bought a new computer.


@diegof Congratulations on your success!


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Here's how to change the drive: iMac Intel 21.5" EMC 2428 Hard Drive Replacement

You're going to have to address the hard drive thermal sensor issue and go with a 3.5" to 2.5" adapter. Doing research on that now. I will have to wait a while as the OWC site is having problems right now.


Here's how to do it when adding a second drive:

Installing iMac Intel 21.5" EMC 2428 Dual Drive Kit

iMac Intel 21.5" EMC 2428 Hard Drive Image


iMac Intel 21.5" EMC 2428 Hard Drive Replacement



45 minutes - 1 hour

iMac Intel 21.5" EMC 2428 Dual Drive Kit Image


Installing iMac Intel 21.5" EMC 2428 Dual Drive Kit



1 - 4 hours

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To add to Mayer's answer:

You'll also need a 3.5" to 2.5" adapter frame and a special thermal sensor as the system requires access to the HD's internal sensor which you've now taken away.

- OWC 2.5" to 3.5" Drive Adapter Bracket

- OWC In-line Digital Thermal Sensor for iMac 2011 Hard Drive Upgrade

While a bit more work I do think adding the SSD behind the optical drive will get you more as this system has a third SATA port. Installing iMac Intel 21.5" EMC 2428 Dual Hard Drive Kit


Thank you. That was the guide I had located. What I need to know is the differences between installing another hard drive or a SSD as I'd like to do.

What do you mean by the thermal sensor issue?


Dan, do you mean I can keep both the actual hard disk and the optical drive and installing a SSD apart? Or should I remove the optical drive?


@diegof - You can have all three running! Keeping your current HDD & Optical drives. The dual drive kit leverages a spare SATA port for the new SSD.

Going with the dual drive setup means you don't need to deal with the frame or the in-line sensor issue as you'll be using your current HDD.

If on the other-hand you are going to switch out the HDD to a bigger one as well, then you'll need the thermal sensor as the Apple drives are custom built drives with the sensor built-in.


Thank you Dan. Maybe I can try the dual drive option. Do you know which kit should I get?


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@diegof - Here's the IFIXIT guide you'll need to follow: Installing iMac Intel 21.5" EMC 2428 Dual Hard Drive Kit Here were using a 2.5" SSD. This is the needed parts: iMac Intel 21.5" Mid 2011 Dual Hard Drive Kit w/needed tools as for the SSD I would go with a Samsung 850 EVO a 250 or 500 GB should do.

Once you install it use your current HD to prep & install the OS (you'll want to make a new user account thats different than yours). Once the OS is installed quit the installer and apply any needed OS updates. Then run Migration Assistant app to copy over your Apps to the SSD and the user accounts and make sure your SSD is the startup drive in your Prefs. Thats it! Done.

iMac Intel 21.5" (Mid 2011) Dual Hard Drive Kit Image


iMac Intel 21.5" (Mid 2011) Dual Hard Drive Kit


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I've been watching the guide. A bit overwhelming! Even it's the best option I think I'll try just changing my actual drive for a SSD addming the thermal sensor.


i would agree w/you assessment diego. i started this myself this weekend and i would call myself a higher level computer geek and having to remove logic board.. nope , nope nope.. replacing dvd drive w/caddy and ssd. no one needs an internal dvd player/drive; bluray ones cost under $50 and are usb 3.0. :)


Anonymous - Diego swapped out his HDD for a SSD instead (see his entry above in December.


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Diego will be eternally grateful.
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