What is the difference between an external SSD and a USB flash drive? How to choose based on usage and points to note for backups

Between an external SSD and a USB flash drive, which one should I buy to save data?There are small models that look similar, ...
Ars Technica

Difference between a USB flash drive controller and an SSD controller?

So I get some of the basic differences between a USB flash drive's controller and an SSD controller, like mentioned here https://superuser.com/questions/919...l ...

External HDD vs. SSD: What are the pros and cons of each drive type?

External SSDs are faster than HDDs, but if you need cost-effective backups or larger capacities, a hard drive may be a better choice for you.

I’ve tested over 100 storage drives and their speeds with this free tool – why I trust it

CrystalDiskMark 9 is a free, open-source tool for testing your HDD, SSD, and flash drive read and write speeds. Here's how it ...
PC World

This USB flash drive is actually a blazing-fast SSD – and it’s 20% off

If you want an external SSD in the form of a thumb drive, the SK Hynix Tube T31 is the way to go. If it looks like a thumb drive and acts like a thumb drive… well, it might not actually be a thumb ...