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macrumors newbie
Original poster
Jan 24, 2019
I have an iMac 27 inch 5k 2018. This has a 1 TB fusion drive with a 24 GB of flash storage in it. This computer is used in a music studio and the hard drive performs terribly. It is excruciatingly slow. I was wondering if any one could help me with the following questions:

  1. Based on my preliminary research the best way to enhance the performance is to create a bootable clone on an SSD (External). Im planning to connect it to the computer with a USB C to SATA, I think the best way to approach this is to use Carbon Copy Cloner and clone my hard drive to the SSD and select this drive as the boot from system preferences. In doing this, I wanted to know whether all my licenses for the softwares and the hardwares will work on the cloned drive as well? Has anyone had experience with this?
  2. I sense a lot of the software resources are large and heavy files. The fusion drive just doesn’t make sense for this purpose. IS the method above the most efficient way to get to a solution?
  3. Is it better to manually install the OS on the external SSD and how will it affect all the licenses and machine IDs that are assigned to my softwares?
  4. What is the ideal format for the best performance for the external SSD. Is it ASFPS or should I go for Mac OS Journaled? If anyone has a better idea or suggestion, please let me know?


macrumors Penryn
Feb 20, 2009
There are no "2018" iMacs. What you have is a 2017-design iMac (perhaps bought in 2018).

The best way to get more performance is to buy an EXTERNAL USB3 SSD, plug it in, and set it up to be the boot drive.
I'd recommend a Sandisk Extreme.
500gb will do fine -- even 250gb will do the job.

Put the OS, apps, and -basic- accounts on the SSD.
By "basic" accounts, I mean, leave large libraries (such as movies, music and pictures) on the internal fusion drive. They'll still work fine there.
The idea is to keep the SSD "lean and clean", with plenty of room for "temp" and swap files.

CCC is a good way to get the SSD up-and-running.
You have to be "selective" about what you choose to clone in the users folder.
Again, CCC will let you "un-check" the libraries to leave behind.

Be aware that if you do a "fresh install", you'll probably have to re-register all your software that requires registration.
I -think- that if you do a CCC cloned copy, most of those registrations will be preserved -- at the very least, some of them.

Insofar as formatting is concerned, I -always- prefer HFS+. But then, I don't run the latest and greatest OS versions...


macrumors 603
Aug 6, 2007
I prefer a TB3 drive/enclosure. USB 3 bus can get saturated faster than TB3. May not ever be an issue for you but just saying.


macrumors 68020
Oct 14, 2018
The Sillie Con Valley
A USB 3/USB-C enclosure is fine for a SATA III drive but it doesn't support TRIM. It's 1/6 the speed of the following:

You want a TB3 enclosure for use with a 970 EVO. Get a 2TB blade. When the warranty is up on your iMac, install that blade inside.

CCC is the wrong tool for this. It doesn't actually "clone" a drive. No it doesn't—read the web site. Besides, it costs $39 that is absolutely unnecessary.

Hook up the external. Download the OS from the App Store and install on the SSD. When it reboots, Migration Assistant will pull everything over from the internal.



macrumors Penryn
Feb 20, 2009
mike wrote:
"CCC is the wrong tool for this. It doesn't actually "clone" a drive. No it doesn't—read the web site."

Mike, I don't know why you keep saying this.
I've used CCC for years (and SuperDuper, too), and I have NEVER had a problem restoring a drive from a cloned backup.
Not. Once. Ever.

Please elaborate on just what CCC "leaves behind" that is otherwise essential to the reconstruction of a boot drive.

I'm sure you know more than I do about this.
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