Freezes on iMac (21.5-inch, Mid 2014), how to fix?

Question

macOS

Hello, recently there was a problem, my poppy started to freeze for 5-10 seconds (repeated every 15-30 minutes), and then everything goes away by itself. I thought it was because of the operating system, I updated to the latest "mojave", the problem remained, then I cleaned the hard drive and the whole computer, it did not help. Standard diagnostics did not reveal anything.
I think resetting to factory settings, is it worth it? Or is some part of the computer damaged?
I would really like to solve the problem because I can’t really play something and it just starts to annoy (((
Thanks for the answer.
Computer information: iMac (21.5-inch, Mid 2014 ), 1.4 GHz Intel Core i5 , Intel HD Graphics 5000 1536 MB .

Answer 1

It is necessary to test the disk, broken / not broken. After that, it will become a little clearer