I like using old PCs. It's a bit like my other pastime which is classic cars, in my case a 1958 Wolseley 1500. Old PCs of 2006 vintage are slow. Mine runs 64bit Windows 10 Pro 22H2 and it runs well with Avast Free 22.4 but with version 22.5 and later there is a very perceptible sluggishness. This also applies when trying to use Avast One. People with the latest sizzling tech won't notice a thing of course.
I guess that the devs don't test on a 2006 vintage PC with a 1.83GHz Intel Core Duo and 4GB RAM. Do they quantify performance reductions or gains from one Avast version to another? I wish that they could put their collective fingers on why this performance difference occurs and so be able to improve performance. Then I can satisfy my craving to run Avast Free 23.?? on my Toshiba Satellite Pro P200. It has such a beautiful display screen.