I'm using a cheap HP laptop, i5-cpu, 8gb-ram, that I got for £100 to run a UC300eth. Swapping between both Mach3 and UCCNC.
Chose to use a retail version of Windows7 I had around, and not win10. Once 7 is fresh and set up, that's the end of it.
You get no updating or other grief.

It's permanently dedicated to running on the machine. Isn't network connected. All cam files are transfered from the cad pc to the laptop via memory card.

Virtual box is also installed on it with a copy of win10 in case I do have the need for net access. Using a virtual machine stops anything nasty from getting into win7.


Getting 80v drivers, 70v psu, to run the nema23 steppers was a good decision.
I've tested the steppers on my mill upto 800rpm / 4000mm/min without a hitch, pretty much the same driver/psu setup as yours except for my steppers are 3mh-4.5A-566oz.

I get my psu's from Aliexpress, they have more selection than what's available in the UK.