A lot depends on what your use-case is going to be. What distro do you want to run? What kind of things do you envisage doing with it? Etc, etc.
Until early 2020, I made do with an elderly Compaq desktop PC, circa 2005-vintage, that had a dual-core Athlon64 X2 in it. Running Puppy Linux as I have for many years, it was quite happy, and even sprightly.
The Compaq's mobo eventually succumbed to dried-out caps, even though Compaq (this was one of the last original Compaqs, pre- the HP buyout) used to specify top-quality components. I don't think anyone could sneeze at getting 15 years + out of any mobo.
I bought my first-ever brand-new box to replace it; an HP Pavilion mid-tower desktop. This has an 8th-gen, 'Coffee Lake' dual-core Pentium G5400 'Gold' with HT. Doesn't sound like much to many folks, but this CPU is more powerful with an ultra-lightweight distro like Puppy than many folks manage running Windoze from a 12- or 16-core i9, i10 or later.
Everything is relative. This, running Puppy along with 32GB DDR4 and SSDs will handle any task I can throw at it with aplomb. I do a lot of video-editing, using Openshot and Lightworks, and for my use-case it's more than sufficient.
Mike.
