Replace HDD with SSD - Mac 2011 - is it worth it? Possible?

Is it possible to replace the hard drive with an external SSD and boot from that?

Yes but don't do anything unless you still have that iMac's original, grey, System Install DVD. A Time Machine backup is also a prerequisite (obviously).

Generally it is possible, but you should contact an Authorized Apple Service Provider for more details.

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A long time ago, I had the HD getting replaced by a SSD in an old iMac from 2007. It performed noticeably better after that, and it still in use today from time to time.

well that model was prone to have the ati gpu die, it's how mine went some years ago

so if it was me then I would not spend too much money on an ssd only for it to die soon after

also apple has long since stopped providing with security updates for the older macOS versions that the model support

and many apps in app store these days will not work on such an old macOS version

stevetheadi wrote:

Is it possible to replace the hard drive with an external SSD and boot from that? I think this Mac is a bit too old to do that but can anyone confirm?

Yes, it is possible to boot from an external SSD. I booted a Late 2009 iMac from an external SSD for a long time.

If you do, I would strongly recommend using a Firewire 800 drive. Your iMac's USB ports – like those on my Late 2009 iMac – are slow USB 2 ports. Even with a Firewire 800 drive, you will not get blinding speed. The Firewire interface will bottleneck sequential read and write transfers. You will gain some on random access speed, and if you eject the internal drive and it stays spun down, your iMac will operate more quietly.

Firewire drives and drive enclosures are nearly extinct, but Other World Computing still sells some:

https://eshop.macsales.com/shop/firewire/on-the-go

https://eshop.macsales.com/shop/firewire/1394/USB/EliteAL/eSATA_FW800_FW400_USB

These have both FireWire 800 and USB 3 interfaces, so you can connect them to your old iMac using Firewire 800, and connect them to a new Mac using USB 3 if you decide to upgrade, and to run Migration Assistant against your old startup drive.

I don't think you need the original OS disks, unless perhaps you're planning on wiping the iMac clean and giving it to someone else.

What you need to do is to avoid erasing the internal drive, unless you already have one or more bootable external drives. If you use a program like Carbon Copy Cloner or SuperDuper!, you could clone your internal drive onto an external startup drive, then switch to that drive without erasing the internal one … leaving a system installed on it as a backup, just in case the external drive ever became unbootable.

Likewise, I believe that if you download the High Sierra installer, you could point it at a blank external drive (or at a clone of your Sierra volume), and update the external drive without affecting your internal one.

You still might want to retire the Mac and get a newer one. Just not for this reason.

stevetheadi wrote:

I have been using my Mac since it was made in 2011. It runs Sierra 10.12.6.

An iMac (21.5-inch, Mid 2011) can run High Sierra.

How to download and install macOS - Apple Support