Thinking of upgrading from a Fusion drive on a Mac? Here’s what you need to know

You can’t swap out the SSD or hard drive in a Fusion combo without a lot of extra work.

apple fusion drive icon
Apple

Today's Best Tech Deals

Picked by Macworld's Editors

Top Deals On Great Products

Picked by Techconnect's Editors

Apple relied on the Fusion drive for years as an affordable middle option between a slow but affordable high-capacity hard disk drive and a fast but expensive high-capacity SSD. The Fusion drive pairs an SSD with very few gigabytes with a much larger HDD. macOS treats the Fusion drive as one logical device, displaying it as a single drive in the Finder. But behind the scenes, it automatically optimizes file storage, so the most frequently accessed files are shifted over time to your SSD, while the HDD holds less-used ones. This is why your Fusion drive Mac can start up quickly, but still be a slug when using Photoshop to edit large images.

This seamless and invisible management is nothing like having two separate drives—it's a stitched-together hybrid. As a result, you can’t separate the two just by upgrading one part without a lot of fancy interactions. And most Macs with Fusion drives have an SSD installed that is difficult to access or is build into the motherboard; the HDD is often quite difficult to access and swap out, or may be impossible to remove.

If your plan is to change out either or both parts, however, start by cloning your Fusion drive to an external drive using Disk Utility, Shirt Pocket’s SuperDuper, or Bombich Software’s Carbon Copy Cloner with Catalina or earlier versions of macOS. Big Sur adds complexity to cloning; read this post at Bombich Software and this at Shirt Pocket for more on the issue. (Macs with Apple’s M1 silicon can’t be cloned fully yet, but no M1 Mac comes with a Fusion drive.)

Apple offers a detailed guide on splitting and restoring Fusion drives that should help if you want to knit back together one or two upgraded components.

This Mac 911 article is in response to a question submitted by Macworld reader John.

Ask Mac 911

We’ve compiled a list of the questions we get asked most frequently along with answers and links to columns: read our super FAQ to see if your question is covered. If not, we’re always looking for new problems to solve! Email yours to mac911@macworld.com including screen captures as appropriate, and whether you want your full name used. Not every question will be answered, we don’t reply to email, and we cannot provide direct troubleshooting advice.

Note: When you purchase something after clicking links in our articles, we may earn a small commission. Read our affiliate link policy for more details.
  
Shop Tech Products at Amazon