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jswebsteve

macrumors newbie
Original poster
Oct 22, 2015
8
19
I have a 27inch 5K iMac that I bought in February. At the time I couldn't wait for a BTO machine as my work machine had died so i needed one off the shelf. I took the one with a 2TB fusion drive.
I'm noticing a slow down in the machine now as it is getting fuller and want to do something to upgrade the storage.

One option would be to split the fusion drive and use the internal SSD for the OS and applications, then add an external SSD in a Thunderbolt caddy.

The other option is to open the machine (I know it will void the remaining warranty) and replace the regular internal hdd with an SSD.

If i went down the internal route, does it still require a temp sensor to be added to prevent the fan running at full speed as was the case with the older iMacs?

Would it be worth rebuilding fusion so that I just have one large volume rather than having to split how I save files?

Any advice and opinion would be appreciated.
 

kdoug

macrumors 65816
Jun 2, 2010
1,025
195
Iowa City, IA USA
I have a 27inch 5K iMac that I bought in February. At the time I couldn't wait for a BTO machine as my work machine had died so i needed one off the shelf. I took the one with a 2TB fusion drive.
I'm noticing a slow down in the machine now as it is getting fuller and want to do something to upgrade the storage.

One option would be to split the fusion drive and use the internal SSD for the OS and applications, then add an external SSD in a Thunderbolt caddy.

The other option is to open the machine (I know it will void the remaining warranty) and replace the regular internal hdd with an SSD.

If i went down the internal route, does it still require a temp sensor to be added to prevent the fan running at full speed as was the case with the older iMacs?

Would it be worth rebuilding fusion so that I just have one large volume rather than having to split how I save files?

Any advice and opinion would be appreciated.
I would be inclined to tell you to open it up and install an SSD. I would also recommend you send it out to do it and not do it yourself. Forget the youtube videos that make it look so easy and simple because it's not unless you've done it before. If there's an Apple authorized repair center in your area that'd be best. You could also send it to MacMedics or possibly contact OWC and see if they do in-house upgrades.
 
Last edited:

Fishrrman

macrumors Penryn
Feb 20, 2009
29,279
13,378
DON'T open the iMac. It will void your warranty, and if you break something inside Apple won't fix it unless you pay.

The 2tb fusion drive has a 128gb SSD/flash portion and a 2tb 7200rpm HDD portion.

"Splitting" the fusion drive would be a relatively easy course of action (of course you have to be BACKED UP first, and I would recommend that your backup be a bootable cloned drive created with either CarbonCopyCloner or SuperDuper).

Then:
- Keep the OS, apps, and your "basic accounts" on the SSD.
- Keep any large libraries you have (movies, music, pictures) on the HDD.

The goal will be to keep the SSD "lean and clean" so it will perform at its optimum speed.

The above-mentioned libraries don't "need speed", as they generally keep files that are seldom-accessed and don't require high throughput speeds when they are.

You're not going to find ANY external drive, thunderbolt or otherwise, that will read/write as fast as the internal SSD that's already installed.
 

Samuelsan2001

macrumors 604
Oct 24, 2013
7,729
2,153
I would be tempted to open it and replace the 2tb hard drive with a sata SSD this will give you the option to create an all ssd fusion drive with the PCIe 128 drive being used for the fastest stuff but with the rest in an ssd as well you should see very little slowdown.
 

AFEPPL

macrumors 68030
Sep 30, 2014
2,644
1,571
England
How about selling the existing device and getting a BTO?
Or just go with an external SSD via TB or NAS drive - remove all the data from the internal drive and split the fusion drive to regain your performance. 128GB is more than enough to run the OS/apps
 
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