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macrumors newbie
Original poster
Jul 14, 2009
TLDR: Help a decidedly non-power user decide between 2TB Fusion, 512 SSD, or 1TB SSD

So I am about to squeeze the trigger on a new 27" and am stuck at the storage options.

Will be replacing a 2008 24" iMac with a 3.06 GHz C2Duo(!) - over the years, I maxed it with 6GB of RAM and replaced the HDD with a 1TB SSD. It is even now still a mostly usable machine for my purposes - email, web, MS Office, VPN to work, large photo library, very light gaming. Sadly, it's stuck at El Capitan, and so I suppose it's finally time to upgrade.

Obviously I tend to keep my machines a long time, and I want to get another 7-10 years out of the new machine. I plan to get the top end 27" and add 32GB aftermarket RAM to get to 40 GB total. I might upgrade to the i9, but will probably keep the 580X. My big question is what to do about storage.

Probably "easiest" would be to suck up the $500 charge and get the 1TB SSD. That seems like a huge price increase considering the actual component cost to apple so I almost want to not do it to spite those SOBs. At >$1000, the 2TB is out of the question.

There's the somewhat more reasonable $100 upcharge to switch to the 512GB SSD, but but 512 might still be just a little too small and doesn't leave much in the way of future proofing (I have more than that now on my current SSD, but suspect that includes a lot of junk built up over the years).

I could just keep the stock 2TB since it'll have the "large" 128GB SSD Fusion Drive & might be enough for me. I figure with 40GB of RAM I won't be doing a whole lot of swapping, so it'll really just be load times for less often used stuff.

I suppose a 4th option is to crack the case and stick an after market SSD in there for a lot less... but even though I've cracked an iMac case many times before, I am not wild about the idea with a brand new machine.

How realistic/usable is it to consider an external SSD to supplement any of the above options? How much faster would an external SSD feel than an internal spinner? For those who have larger fusion drives... how does that compare to all SSD storage in everyday usage? Thoughts/advice?

It would be crushing to wait 11 years, spend $2500, and wind up with a computer that feels slower than my 2008 machine b/c I'd be going retrograde from SSD back to HDD.


macrumors 68020
Feb 14, 2007
I have a 2015 27" 5k iMac w/ a 2TB fusion drive. , I also am thinking about upgrading. I have 4 Ssd's on my iMac now 3 on USB 3 and one on TB2. The USB 3 drives are faster that the thunderbolt. I am happy with the SSD speed, see screen shot. Not as fast as internal but not bad. Ion the TB connected SSD I have windows 10 installed and it works great. Think I my just go for the 512 SSD option in the new iMac. I have 3 other spinning drives connected to a TB2 dock. I would like to use the TB2 dock on my new iMac as a USB3 hub. Does anyone out there know if it will work as well as it is on my current iMac?

Screen Shot 2019-03-20 at 6.23.42 PM.png
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macrumors 604
Dec 19, 2004
Get the 512GB. If you need more storage in the future. Use external HDD/SSD. For about $250 you could add an external USB 3.1 Gen 2 SATA SSD. A bit more for USB 3.1 Gen 2 with NVMe.

Given how sealed iMacs are and how long you want it. I’d want to minimize risks of component failure.

While SSD do fail. They have a far lower annual failure rate than HDD. Going by the research I’ve read from Carnegie Mellon University and Backblaze reports.
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macrumors 601
Mar 12, 2002
BrisVegas, Australia
I just sold my Mid-2010 27” iMac. I did a DIY upgrade to 256GB SSD boot drive and 3TB HDD.

Only have a 512GB SSD on the new MacBook Pro, but the best advice I can give is start with a fresh slate, keep all your old files on external drives and don’t move then to the new iMac. When you realise how much unused old junk you actually have, you realise you don’t need all that much internal storage. Unless you’re downloading lots of movies, TV shows, etc...

I don’t know how the new iMac rates for easiness of DIY upgrade, but I would use it for a while - see how much storage you need then DIY upgrade in a year or two. Saves a packet, honestly the price of BTO options is just ridiculous.


macrumors Core
Feb 20, 2009
My opinion only:

1tb SSD isn't worth the extra money -- unless you actually EARN money with your computer and can justify (and write off) the cost that way.

Then again, some folks have enough $$$ so that $500-600 doesn't mean much to them...

I say, get the 512gb SSD (the sweet spot between price and size), and add external USB3 SSD storage as needed. 2.5" SSDs (even 1tb models) are CHEAP now. You would want TWO of them:
1. your "primary external" drive
2. a backup of your primary external

Use a cloning app like CarbonCopyCloner or SuperDuper to "keep the backup current".

There is NO PROBLEM at all setting up your photo library to run from an external SSD.
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