A How-To For Upgrading Your iMac

By Kean Bartelman, Macworld    Aug 18, 2012 7:33 pm

Now that it seems that Apple releases new Macs on a less frequent basis, do-it-yourself kits are becoming an increasingly popular option. However, because of its sleek design and fragile parts, upgrading an iMac is not for the faint of heart. If you’re up to the challenge, you can do it, using tools such as the ones provided in OWC’s Internal SSD DIY Kit. You can add a solid-state drive (SSD) to your iMac and see a serious boost in performance

We used a kit for the 2011 21.5-inch iMac, which sells for $58 directly from OWC. It includes an 11-piece tool kit, microfiber cleaning cloth, the necessary data and power cables, two suction cups for the iMac glass screen removal, and a thermal-safe adhesive mounting set. The SSD itself is not included; users can purchase and install one of the several SSDs that OWC recommends, and if you buy an SSD at the same time as the kit, OWC takes $15 off the price of the kit. We used the 240GB Mercury Extreme Pro 6G SSD, which sells for $320 dollars.

Under the hood

Installing an internal SSD in an iMac is a fairly arduous undertaking, even for anyone who’s done it before. OWC recommends watching the tutorial video before purchasing the kit. If you feel like your skills aren’t up to par, OWC will install the drive for you via their Turnkey Upgrade Installation Program which also gives you the option to upgrade your memory, replace the main bay hard drive, or add up to three internal SSDs.

Tools: The OWC Internal SSD DIY Kit (photo courtesy of OWC).The process of dismantling an iMac is riddled with difficult tasks from start to finish, and each step requires a fair amount of caution and precision. In the first two steps, you must remove the glass screen cover by using the two suction cups provided in OWC’s kit. After gently detaching the glass, you then remove eight screws that hold the screen in place, making sure to not touch the screen itself, as the oils from your hands are extremely difficult to wipe off the screen.

Once you have removed the screen and placed it on a static-free surface, you will then be instructed to remove the internal fan, AirPort card, optical drive, and even the logic board. All in all, this requires you to remove 13 more screws and disconnect a handful of cables inside the iMac. When all of the items have been properly removed and disconnected, you can place the SSD against the back wall of the iMac directly underneath the location of the optical drive.

After the new SSD has been connected properly, you retrace your steps until you have your iMac put back together. From start to finish, placing the new SSD in our iMac took approximately two hours to complete.

Speed improvement

Upgrade: OWC’s Mercury Extreme Pro 6G SSD (photo courtesy of OWC).To gauge the speed improvement, we first ran our Speedmark 7 series of benchmark tests on a stock 21.5-inch 2011 iMac with a 2.7GHz Core i5 quad-core processor, 4GB of RAM and a 1TB hard drive, running Lion 10.7.3. After installing the SSD behind the optical drive, we selected it as the boot drive and put the system through the Speedmark tests again.

As you can see from the result tables below, in comparison to the stock hard drive, the SSD-equipped iMac tested more than twice as fast during certain tasks, such as duplicating a 2GB folder, zipping a 4GB folder, and unzipping a 4GB folder. Not surprisingly, CPU and GPU-intensive tests like MathematicaMark and CineBench showed little or no improvement.

Overall, the upgraded system was 40 percent faster than the stock configuration, scoring an impressive 323 in our aggregate Speedmark tests, versus the 227 score that the stock iMac registered.

Testing outside of the box

If you don’t want to change the iMac’s internal drive, another possibility that’s worth exploring is an SSD external drive connected via Thunderbolt. Using a Seagate Thunderbolt adapter with the OWC SSD, we connected the drive to the 2011 iMac’s Thunderbolt port.

The iMac’s benchmarks were similar to the results with the SSD installed internally, with the exception of one test–the large file Zip test, which took nearly twice as long when the SSD was attached via Thunderbolt. Other tests results that were faster with an internal SSD than with the stock 1TB hard drive maintained their speed advantage when the SSD was attached externally. The benefit here is that the SSD is much easier to connect to your Mac and is accessible if you want to use it with another machine.

Thanks for the memory

After testing with the Mercury Pro 6G SSD, we upgraded the memory in our iMac from the standard 4GB to 32GB of 1333 MHz DDR3 RAM, using an OWC memory kit. We booted with the SSD, ran the same benchmark tests, and found that the extra RAM did not make a noticeable difference. In fact, the iMac with the upgraded RAM scored a 323 overall; the same score that the iMac with the stock 4GB of RAM.

The RAM did yield higher scores when our iMac booted off of the stock 1TB hard drive. During a multitasking test, in which we zipped a 4GB folder, converted 42 AAC files to 160 kbps MP3s in iTunes, and ran a Speedmark script in Photoshop, the RAM upgrade helped to shave nearly a minute off of our Photoshop test and about 30 seconds off of our zip folder time. Ultimately, the iMac with a 1TB hard drive and 32GB of RAM scored a 239 in our aggregate Speedmark tests, 12 points higher than the stock iMac with 4GB of RAM.

Adding RAM helps most when using hard drives. When working with multiple applications or extremely large files, if your app runs out of RAM, it needs to get data from your main storage. Spinning hard drives are much slower than RAM or an SSD. If your main storage is an internal SSD, a huge RAM upgrade may be overkill for all but the most demanding of users and tasks.


Before you decide you want to open up your iMac and upgrade the components, make sure you are confident in your ability to perform this upgrade without destroying your computer. OWC’s kit has the tools that you will need (other companies such as iFixit also sell tools for working on your computer), but doesn’t make the task at hand any easier. You may want to find a service that will perform the upgrade for you. All that said, adding an SSD to an iMac will certain boost its performance, and can be a more affordable way to make a great machine even better.

Republished from PC World. (View original version.)





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