Speed up Your Older iMac by Booting to an External Solid State Drive

In this article, you will learn how to speed up your older iMac by booting to an external solid state drive. For this example, you will discover how you can boot to Mac OS Mojave using a Samsung T5 SSD.

Before we get into how to do it, let’s cover a few reasons why you might want to consider booting to an external SSD with Mac OS Mojave installed. This may surprise you, but even in 2019, some iMacs come with a 5,400 RPM spinning hard drive installed.

Hard drives that run at 5,400 RPM or 7,200 RPM are noticeably slower than modern solid state drives. A solid state drive is also slightly faster than Apple’s Fusion drives, which are a combination of flash storage and a traditional spinning hard drive.

If you don’t upgrade to an SSD when you order your iMac, the only way to upgrade to a solid state drive afterward is to remove the iMac screen. Removing the iMac display screen is the only way to gain access to the inner components of the computer. A more cost effective and less intrusive method is to use an external solid state drive instead, like the Samsung T5.

Booting from a solid state drive like the Samsung T5 should give you a boost in performance, especially if you are running an older iMac with a 5,400 RPM hard drive. On top of booting from an external solid state drive, it is also a good idea to store your media files on another solid state drive separate from your operating system.

Having two solid state drives will speed up your photo and video editing workflow and video rendering times, and as of 2019, the prices on solid state drives have come down considerably. For a step-by-step tutorial on how to set up an external boot drive with Mac OS Mojave, check out the video tutorial in this article.

If you are running a similar setup using solid state drives, let me know in the comment section below.

Craig Beckta's picture

Craig Beckta is a portrait and fashion photographer based out of Halifax, Nova Scotia. Craig currently has over 160 photography and videography tutorials on YouTube.

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THe older ones the swap was scary but easy. The new ones the swap is scary and a pain in the butt (i broke my screen lol).

This is probably not the worst idea.

The title of article is related to Speed... and I was really curious how much of a speed increase you feel this made? Specifically related to working with PH and LR... ?

Hi George, it depends on a number of factors. Normally a system hard drive would be faster than an external drive. But a 5400 rpm drive is pretty slow. Fusion drives can be pretty fast for some tasks. Where the big difference is, is the time it takes for a standard spinning drive to find the information and spin up if it is a sleep. I did a test and when my iMac was idle it took 28 seconds for Adobe Premiere to fully open. Once the drive was awake it was roughly 7 seconds. The Samsung T5 was about 6 seconds at its slowest. For some tasks it will be noticeable. Plus it is easier than removing the screen and replacing your system drive.

Amazing. Didn’t know you could do that. Thank you.

I replaced my dying 1TB 7200 RPM Fusion HDD on my Late 2012 iMac with a 1 TB Samsung Evo SSD, and it definetely got faster. However, There is no way around the fact that my CPU is slow for most tasks when compared to more modern machines. My iMac was specced with the fastest CPU one could buy and it is definetely showing it's age.
It's not going do miracles. So don't expect CPU intensive tasks to get any faster.

how does this compare to a fusion drive?

Thanks for the instruction. I have done what you said and it functions normally. However it took almost a minute to boot up.It stuck at the apple logo for around 30 secs before the loading bar comes out and load. Do you know what causing this problem? Wrong Thunderbolt peripheral slot? Blackmagic Read and Write is around 500mb.

I can compare the booting time vs my Macbook Pro 2015 retina ssd.. Read 1000mb, Write 400+mb

With this setup, what else gets installed on the new SSD Startup Disc? Do applications, user data, etc, get put there too, so the old Hard Disk is unused?