Running dual SSDs in late '09 iMac?

[molan]

I fitted a 500Gb SSD in my iMac about a year ago and it had been running really well until a power outage last week. There are now some major issues with the drive but it's being repaired under warranty.

Repair is going to take maybe 14 days as I have to post it off and wait for the return.

As I have to rip my iMac open I thought about maybe replacing the optical drive with a second SSD. I could then run mu OS and maybe applications on one SSD and use the other for storage. I also have an NAS running so I don't desperately need lots more storage but thought that an additional backup drive might be useful anyway.

I have a couple of questions:

1) If I use one SSD for the OS and apps and then want to run something like picture and audio editing software with files on the 2nd SSD will this be noticeably slower than having both the apps & source material on the same SSD?

2) How big a drive would I need if it's only for OS & apps? I thought about getting a smaller 250Gb drive for this and using the 500Gb for storage. However the cost of another 500Gb is 'only' about 60% more than the 250Gb so it's relatively cheaper.

If the whole idea of running a 2nd SSD for the OS is not particularly beneficial I could just live without the iMac for a couple of weeks - I have an old Air to use but it's painfully slow with a fixed 2Gb of RAM

 

[Samuelsan2001]

1) shouldn't make too much difference.
2) drive size is personal preference and down to what you want to spend.

As a quick tip you can use this set up to create a fusion drive with a few command lines found on google, with a double ssd fusion drive it will all be seen as one volume and the OS will organise it all for you. This will be particularly quick fusion solution.

https://www.techrepublic.com/article/pro-tip-how-to-create-and-disable-a-fusion-drive/

 

[YanniDepp]

Removing the optical drive and fitting two disks instead was a big deal a few years ago, when SSD prices were ridiculously expensive. The idea was to use a 128GB SSD or so for the OS, and have something like a 1TB hard drive to store all your documents.

These days, SSD prices have come down so far that it's really not worth it unless you plan on storing every document you've ever made on the iMac and plan on putting a 4TB hard drive in it. You might as well just swap the hard drive for a 1TB SSD and keep the optical drive. 1TB should be enough for anyone's day-to-day use (all my Macs have 500GB SSDs). If it's not, just move all the big videos you don't use often (iTunes store purchases, iMovie projects, questionably-obtained videos) to an external hard drive.