Fusion v SSD

I had a 2011 27" iMac with a 250 SSD and an 1TB HD, both interior and not a fusion drive. I never filled up my SSD more than a bout 150 GB, leaving around 70 GB free space for efficiency of system and applications. I kept my photos and music libraries on the HD. The trusted iMac died a couple of months ago and was replace with new iMac with a 500 GB SSD. I have a number of external HDs, both rotational and one SSD for data storage.

So my recommendation would be to go with the largest SSD drive your budget can afford. External HDs are very inexpensive if you get to the point where you need more storage,

Well, one can store 8 times as much data. 256GB is fairly small in this day and age. Depends on what you are going to use it for. SSDs are faster.

Personally, I'd go with the 256 SSD and add additional external SSD storage from a 3rd party supplier like OWC, probably as a USB3 drive with it's own power supply. Adding a larger internal SSD from Apple will be significantly more expensive.

A Fusion drive is as its name implies a fusion of an SSD and a traditional mechanical drive into a single storage volume.

The main question you need to answer then, is, do you need 2TB of storage space or are 256GB enough?

256GB would be around 0.25TB.

The Fusion drive uses the SSD portion to increase the speed of file transfer for frequently used files. so it keeps them on the SSD.

So while you get more storage, you get better speed for more frequently used files than a traditional mechanical hard drive, but its still slower than a regular SSD. Since it will still need to look for files in the mechanical portion of the fusion volume at some point.

If space is not a concern, go for the SSD. If you need a lot of storage then go with the Fusion drive or as mentioned the 256GB SSD and an external drive with more space.

Personally, I would opt for the SSD. HDD (which is part of a Fusion drive)

being a mechanical device will fail. It's not a matter of if but when. Some

seem to last longer than the usefulness of the computer they are installed in

and others will die in less than a year and others any time in between.

That doesn't mean SSDs won't fail. There is the case of what we called when I

was in the electronic design business of "infant mortality" meaning a failure

in less than a year due to manufacturing defects. If this doesn't happen, then

it will last years. The memory cells do have a limited number of times that they

can be erased and written to. Manufacturers have ways to optimize that lifetime

and the typical user will likely find their computer woefully outdated before that

point is reached where memory cell lifetime is an issue.

So am I going with this? Because of their design, iMacs are difficult to repair

(read expensive). If something fails during warranty or additional AppleCare

coverage, it's not an issue. Beyond that, it will all come out of your pocket.

FWIW, I have a Late-2012 iMac with a Fusion Drive. The first year they were available from Apple. So far, mine is still working just fine. I also have a Late-2015 5k iMac with a Fusion Drive and it's fine as well. I also have various laptops from Apple and others, all with SSDs. None smaller than 512GBs.

I agree with the ext hd bit I use a samsung 500GB it's gets it power from the usb port pretty good little box