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macrumors newbie
Original poster
Oct 17, 2020
My iMac 27" 2017 with fusion drive starts very slowly with Big Sur, 4-5 minutes until ready, just 2 usual login items.

There's SSD in the drive and it should start as fast as by previous versions of macOS.

Is it normal for the fusion drive to look like this?

Screen Shot 2020-12-11 at 11.44.09.png

SSD not separated and overloaded, it should be only for the OS.

Hope for a solution to have better start time.


macrumors 68020
Oct 19, 2007
Blue Mountains NSW Australia
Alas you have an extremely limited 1TB Fusion Drive which only has a 28GB blade drive, and the loaded system etc on your iMac tells us it is 112GB, which of course the blade cannot handle so the by far greater part is installed on the slow old platter drive.

Your best option may be an external SSD connected by USB or Thunderbolt. Go through the threads this has plenty of coverage.


macrumors 603
Aug 20, 2015
Alas you have an extremely limited 1TB Fusion Drive which only has a 28GB blade drive
What a burn! I had an earlier generation of 1TB Fusion Drive which at least had a 128GB SSD. I just can't believe Apple skimped out so badly as to ship one with a mere 28GB, which is not at all adequate.

(I say "had" because the SSD part of mine just started getting hammered with wear after a few years and I had to replace it. Turns out that the logic of the Fusion Drive does a lot of reading and writing as active data is moved to the SSD. More here:
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