One thought - can an iPad Pro replace my need for a desktop? It will require a lot of learning new apps on my part but that time may have come.
I buy my Intel systems bleeding edge (except for the OS), and always look for F@H compatibility. Not sure if F@H can work on an A10x processor - but could it work inside a browser, folding away?
In all fairness, I spend almost as much on a new PC as I would buying a new Mac. Being in the business, I would never expect a five year old PC to be functional if I didn't buy high end.
So the choice will probably come down to which OS I want to use - Win, OS/X or IOS, or which combination at one time.
Folding at Home is not a good idea on anything that is dependent on a battery for its operation.
There is F@H for OS X and macOS.
Macs last far longer and better than PCs do. . . and remain functional even longer. In addition, the Mac can allow you to use all of those OSes and then some.