Hey Guys, as you may know, I have three computers in regular use.
1/. I keep XP Pro on a CAD station built for me many years (10?) ago to run 3D CAD SolidWorks 10 - it has never seen the internet so needs no AV and is just so fast! Intel(R) Core™2 Quad CPU Q8300 @ 2.5GHz 4.0GB RAM. It also runs Serif PagePlus and PhotoPlus.
2/. Have bought Dell Latitude E6420 Intel(R) Core™ i7-2640M CPU @ 2.8GHz x 4 with 7.7GiB RAM dual boot with ubuntu 16 and Win10. Runs Epiphany and Midori plus DuckDuckGo. GMX free Webmail and Geary mail, Shotwell, Screenshot, Libre Office, FocusWriter, Gimp and Serif PhotoPlus windows software on Linux - the better of the two! FreeCAD etc. Life is good now. Favourite toy at moment is Tails 4.2.2 on a stick packing Tor Browser; so fast and silent that I keep forgetting that I am only in RAM,
3/. Perhaps strangely I find that I am using my rescued (from Vista) HP G60-120EM Intel(R) Core™ Duo 2.00Ghz 3.00 GB RAM ruining Trisquel GNU-Linux 8. I do not know if this because of the full English keyboard, number pad, scroll bar, larger screen or Trisquel OS. I think I just like Trisquel – even using Ffox again - Abrowser as it is set up so nice out of the box. 
It used to be said that certain software like 3D CAD and CAM could only make use of or address so much defined RAM given also at the time and probably still so, only one OS. Would it then be okay to drop ubuntu on the Dell Latitude E6420 and install a lighter Linux like Trisquel 9 or a medium OS like MX? Would this lead to known issues running FreeCAD or running wine dependent or demanding windows programmes? Would it be theoretically faster or slower?
Could some of the more knowledgeable community members get my head in better shape regarding Hardware vs OS vs Software vs RAM vs Swap, issues – please? Light or Heavy, David vs Goliath, Mini Monte Carlo Rally, Lotus vs Lard, sledgehammer to crack a nut etc. 16.04 LTS vs 20.04, Trisquel vs ubuntu footprint – speed? Is there a sweet spot for harmony? 
Part of design engineering may include FEA – Finite Element Analysis where a component or structure is resolved into a mesh and loading, restraint and material are specified and quantified. The fatigue analysis number crunching was often left to finalize overnight with large or complex items; no problem. This may be reduced to a couple of minutes shortly when quantum computing becomes affordable by engineering firms, but would be a waste of resource just to run CAD, type a letter or edit in the RAW? 