Replace Fusion Drive in 27" iMac

Hi Servant of Cats,

Apologies for having taken so long to respond to you. I've been thinking too much about my situation. I still need advice, and more knowledge, before proceeding with the external SSD.

Will the new external SSD (connected to the 27" iMac via a USB-A cable with an adapter) be replacing the existing Apple SSD Controller of 28GB capacity? This is indicated as an APPLE SSD SM00321.

I am planning to purchase an SSD (LaCie) to be my new startup drive. Which would be better, a 1TB or a 2TB SSD? Is larger better, or is smaller OK? I need some education as to what it actually does.

Many thanks for all your previous comments and suggestions,

peterpatter.

Hi Servant of Cats,

Thanks so much for your advice. I like your second suggestion above. However, my 2017 iMac only has USB-A ports and an ethernet port on the back. Can I get an adaptor so one of these ports can become a USB-C / Thunderbolt port, to get the USB 3.1 Gen 2 speed? I've decided to go for the LaCie 2TB SSD. My Time Machine backups are on a 4TB external SSD.

Again, many thanks,

peterpatter.

Hi Servant of Cats,

Thanks so much for your information. As I've never, so far, had need for the USB3 ports, I had forgotten that they were there. How stupid can I be? To transfer files between my iMac and my MB Air (M1 chip), is a cable between the respective USB3 ports the best way of doing this?

At the moment both Macs are running OS Ventura. Is it necessary for them both to be on them same OS when transferring files via a cable, or wifi, or does this not matter?

By the way, based on information from you, and others, I will soon be purchasing a 2TB LaCie SSD to be my new startup drive.

Many thanks,

peterpatter.

Hi Servant of Cats,

It's me again. At my local Apple Store, the LaCie rugged 2TB SSD is indicated as being suitable for an iMac (Retina 5K, 27-inch, 2019–2020). As my iMac is a 2017 model, is it OK to go ahead with the purchase? The 2TB model costs quite a bit more than the 1TB SSD.

Many thanks,

peterpatter.

Hi Servant of Cats,

Thanks so much for that useful information. Does it matter if the 27" iMac is on macOS Ventura 13.7.4 with an Intel Core i5 processor, while the 13" MBA is running with Ventura and an Apple M1 chip? If I upgraded the MBA to macOS Sequoia, would they still be compatible with each other for transferring files between them, using either a thunderbolt cable or iCloud?

Do you know how far I can upgrade my iMac OS, or is Ventura the limit for it? I've read somewhere that I probably can't go up beyond Ventura.

By the way, I've now bought a 2TB OWC Envoy SSD to use as the startup drive for my iMac, so I'll be using the information that you and others have provided, to proceed with this. Wish me well with speeding up my iMac.

Cheers,

Peterpatter.

Thanks so much for your advice, above. Would the external SSD appear in Finder and as a Desktop Icon, in addition to my LaCie backup drive, which is used for Time Machine?