5K Retina 27” 2017 drives upgrade

Very involved to replace the Internal dreive...

https://eshop.macsales.com/installvideos/imac_27in5k_14late_hdd/iMac17-1/

Might be better to go with external Thunderbolt SSD...

https://eshop.macsales.com/item/OWC/TB3TBV4T04/

https://eshop.macsales.com/shop/owc-envoy-pro-sx

My 2019 i21.5" Mac booting from TB3 external drive...

I would recommend visiting OWC’s website. they are a good source for SSDs (both SATA and NVMe) for your Mac. they are also who I would recommend for sourcing your SSDs. and they also have DIY install videos on their site. you could use those videos to determine if the operation is something you would be comfortable doing, or if you will need to farm it out to a professional.

Easier to use an external nvme drive and boot from that one. (Clone)

They cost more because you are buying high quality stuff that works. Buy cheap stuff and you throw the dice , meaning maybe it works and maybe not. Not the time to be penny wise and pound foolish. Also, going external is MUCH smarter than doing surgery on an old and possibly brittle machine.

You have been given high quality advice from multiple experienced users, time to take it my friend.

martiandj wrote:

Always felt weird for me to boot from external. However, do you know if i can use Samsung, WD for that ? Or any brand for that matter

if we are talking an external drive, I personally use a Samsung T7 SSD to run Catalina on my iMac when I need the older macOS.

I am aware of OWC but they are very pricey in my opinion which is why i would like to use brands like Samsung, WD and others that i can find cheap on Marketplace.

I totally get the desire to be frugal. I'm probably one of the biggest cheapskates on the planet. but I don't get that when it comes to apple replacement hardware. you bought a premium product at a premium price. why cheap out on replacement hardware. I mean, would you put a Honda engine in a Ferrari?

Personally, I suggest you contact OWC (MacSales.com) Customer Support and see which of their external SSDs would best suit your Mac model, work requirements and budget. They are considered by most of the experienced contributors here to be the premier Mac hardware provider. I have 9 of the OWC SSDs on two of my iMacs (mine and my wife's) and won't have anything else. Too may reports here in the ASC of problems with WD, Samsung, LaCie and other SSDs. The the only problems I've had with SSDs or external drives have been with Samsung and LaCie.

If you go the external SSD route it's something you can easily take with you when you upgrade to a Silicon Mac and and be used for a backup system or other storage.

As you've already been told, you get what you pay for.

It's not that simple to benchmark fusion Drives as it depends how often & what size files you're reading & writing, but example on my 2019 iMac 4K...

1TB Fusion 1st run 1GB files...

Same after 3 runs of 4GB files...

Same after 4 runs of 4GB files...

OWC external after 4 runs of 16GB files...

Macs can be fussy about which hardware is installed in them. but they don't appear to be as fussy when it comes to external drives. although, I'm unsure about "any" drive. I only have one external boot drive, so I can only confirm that it (Samsung T7 SSD) does work.

but if you are going to use it as your main boot drive, you may want to look at the much faster (but more pricey) options that BDAqua has provided links for.