I was always able to install my new Asus board and Intel cpu on an existing Asus \Intel\Windows OS installation. Windows would boot nicely. I assumed there were enough similarities going on that it was not necessary to fresh install the OS for each motherboard and cpu upgrade.
Is Win 10 as robust as previous OSes, viz., Win 95 + ? Probably.
How similar is the new computer to the existing install and are the boards both from the same brand ?
There's a chance replacing the current set up with a new board and cpu will work depending on these factors (subject to anyone who has actually tried it
) but a fresh install is always recommended. It will leave a smaller footprint on the disk, e.g., no Win.old files, and installs the latest application drivers and software upgrades.( Here the 10 install downloaded the latest GTX drivers . Like huh ? How secure is that ? I am not happy :thumbsdown:.)
Anticipating your particular situation of fulsome upgrades, I suggest you do a fresh install of Windows 10 on the new computer and add the peripherals later.
Save your data somewhere else, burn the iso and load'er up.
If you have more than one drive, then as your back-up you should have a good bootable clone on the lesser drive. Look at a disk application called Casper.