Advice on external drive for iMac

[Luis Ortega]

I have a 2020 intel iMac and I want to get an external drive that I can use as a fast scratch disk for photoshop and also have a partition for windows through bootcamp.
I plan to use one of the thunderbolt 3 ports on the iMac and would like advice on what sort of drive and caddy would be good for me.
I would like for the scratchdisk not to slow down my use of photoshop that is on the iMac‘s very fast internal drive, and I also want to be able to boot into windows at startup when I need.
I would like for the scratch disk performance to be as good as just letting photoshop use the system drive as the scratch disk while also running the software.
Will I need something as fast as an nvme blade drive or will some other type of ssd be sufficient for my purpose?
Thanks for any advice.

 

[mmkerc]

You might want to look at the Samsung T5 or T7 SSD drives.

 

[chabig]

I have two T5s, and a T7. For some reason, one of them won't even mount on my M1 Mac mini. I think it's a firmware problem and Samsung hasn't updated the firmware to fix it. There are internet discussions about this problem.

I also have a Sandisk Extreme portable SSD that works perfectly without any issue whatsoever. I prefer it.