Help - Ext SSD

[glynnwaterworth]

Hi,
I have an iMac with the Fusion Hard Drive, which since installing Big Sur is now running slower.
Would an external SSD possibly a Thunderbolt one speed the Mac up ?.
I have tried an old SSD connected by USB and this seems to work ok but wondered if a new thunderbolt device would be much better.

Many thanks,
Glynn

 

[mdgm]

Which model iMac do you have and which version of Thunderbolt does it have?

What capacity Fusion Drive does the Mac have? Depending on the capacity and when you got it, it may have a very small SSD. SSDs have limited writes and with a Fusion Drive using a small SSD it's only a matter of time before the SSD's rated number of write cycles are used up.

What kind is the old external SSD? A USB3 SATAII 2.5" SSD?

A Thunderbolt NVMe SSD would be the fastest option but it can also be pricey. It's a lot faster than what a Fusion Drive would be.

Using an external doesn't risk breaking the machine opening it up or require paying expensive fees to a technician to install a SSD.

I have a 2011 iMac with iMac -> TB(1/2) cable -> Apple TB3 to TB2 adapter -> TB3 dock -> TB3 NVMe drive. It's faster than a single internal SATA III SSD would be, but due to TB1 on the 2011, not a lot faster.

If your Mac has TB3 ports or you get an AC powered drive (i.e. not bus powered) then you don't need a Thunderbolt dock or hub.